diff --git a/xml/System.Text.RegularExpressions/RegexParseError.xml b/xml/System.Text.RegularExpressions/RegexParseError.xml
index 4801ee53707..8a19355fdfc 100644
--- a/xml/System.Text.RegularExpressions/RegexParseError.xml
+++ b/xml/System.Text.RegularExpressions/RegexParseError.xml
@@ -13,8 +13,16 @@
     <BaseTypeName>System.Enum</BaseTypeName>
   </Base>
   <Docs>
-    <summary>To be added.</summary>
-    <remarks>To be added.</remarks>
+    <summary>Specifies the detailed underlying reason why a <see cref="T:System.Text.RegularExpressions.RegexParseException" /> is thrown when a regular expression contains a parsing error.</summary>
+    <remarks>
+      <format type="text/markdown"><![CDATA[
+
+## Remarks
+
+This information is made available through <xref:System.Text.RegularExpressions.RegexParseException.Error>.
+
+          ]]></format>
+    </remarks>
   </Docs>
   <Members>
     <Member MemberName="AlternationHasComment">
@@ -34,7 +42,7 @@
       </ReturnValue>
       <MemberValue>17</MemberValue>
       <Docs>
-        <summary>To be added.</summary>
+        <summary>An alternation construct in a regular expression contains a comment.</summary>
       </Docs>
     </Member>
     <Member MemberName="AlternationHasMalformedCondition">
@@ -54,7 +62,7 @@
       </ReturnValue>
       <MemberValue>2</MemberValue>
       <Docs>
-        <summary>To be added.</summary>
+        <summary>An alternation in a regular expression has a malformed condition.</summary>
       </Docs>
     </Member>
     <Member MemberName="AlternationHasMalformedReference">
@@ -74,7 +82,7 @@
       </ReturnValue>
       <MemberValue>18</MemberValue>
       <Docs>
-        <summary>To be added.</summary>
+        <summary>An alternation construct in a regular expression contains a malformed reference.</summary>
       </Docs>
     </Member>
     <Member MemberName="AlternationHasNamedCapture">
@@ -94,7 +102,7 @@
       </ReturnValue>
       <MemberValue>16</MemberValue>
       <Docs>
-        <summary>To be added.</summary>
+        <summary>An alternation construct in a regular expression uses a named capture.</summary>
       </Docs>
     </Member>
     <Member MemberName="AlternationHasTooManyConditions">
@@ -114,7 +122,7 @@
       </ReturnValue>
       <MemberValue>1</MemberValue>
       <Docs>
-        <summary>To be added.</summary>
+        <summary>An alternation in a regular expression has too many conditions.</summary>
       </Docs>
     </Member>
     <Member MemberName="AlternationHasUndefinedReference">
@@ -134,7 +142,7 @@
       </ReturnValue>
       <MemberValue>19</MemberValue>
       <Docs>
-        <summary>To be added.</summary>
+        <summary>An alternation construct in a regular expression contains an undefined reference.</summary>
       </Docs>
     </Member>
     <Member MemberName="CaptureGroupNameInvalid">
@@ -154,7 +162,7 @@
       </ReturnValue>
       <MemberValue>20</MemberValue>
       <Docs>
-        <summary>To be added.</summary>
+        <summary>The group name of a captured group in a regular expression is invalid.</summary>
       </Docs>
     </Member>
     <Member MemberName="CaptureGroupOfZero">
@@ -174,7 +182,7 @@
       </ReturnValue>
       <MemberValue>21</MemberValue>
       <Docs>
-        <summary>To be added.</summary>
+        <summary>A regular expression defines a numbered subexpression named zero.</summary>
       </Docs>
     </Member>
     <Member MemberName="ExclusionGroupNotLast">
@@ -194,7 +202,7 @@
       </ReturnValue>
       <MemberValue>23</MemberValue>
       <Docs>
-        <summary>To be added.</summary>
+        <summary>A character class in a regular expression with an exclusion group is not the last part of the character class.</summary>
       </Docs>
     </Member>
     <Member MemberName="InsufficientClosingParentheses">
@@ -214,7 +222,7 @@
       </ReturnValue>
       <MemberValue>26</MemberValue>
       <Docs>
-        <summary>To be added.</summary>
+        <summary>A regular expression has a non-escaped left parenthesis, or misses a closing right parenthesis.</summary>
       </Docs>
     </Member>
     <Member MemberName="InsufficientOpeningParentheses">
@@ -234,7 +242,7 @@
       </ReturnValue>
       <MemberValue>30</MemberValue>
       <Docs>
-        <summary>To be added.</summary>
+        <summary>A regular expression has a non-escaped right parenthesis, or misses an opening left parenthesis.</summary>
       </Docs>
     </Member>
     <Member MemberName="InsufficientOrInvalidHexDigits">
@@ -254,7 +262,7 @@
       </ReturnValue>
       <MemberValue>8</MemberValue>
       <Docs>
-        <summary>To be added.</summary>
+        <summary>A hexadecimal escape sequence in a regular expression does not have enough digits, or contains invalid digits.</summary>
       </Docs>
     </Member>
     <Member MemberName="InvalidGroupingConstruct">
@@ -274,7 +282,7 @@
       </ReturnValue>
       <MemberValue>15</MemberValue>
       <Docs>
-        <summary>To be added.</summary>
+        <summary>A grouping construct in a regular expression is invalid or malformed.</summary>
       </Docs>
     </Member>
     <Member MemberName="InvalidUnicodePropertyEscape">
@@ -294,7 +302,7 @@
       </ReturnValue>
       <MemberValue>3</MemberValue>
       <Docs>
-        <summary>To be added.</summary>
+        <summary>A Unicode property escape in a regular expression is invalid or unknown.</summary>
       </Docs>
     </Member>
     <Member MemberName="MalformedNamedReference">
@@ -314,7 +322,7 @@
       </ReturnValue>
       <MemberValue>12</MemberValue>
       <Docs>
-        <summary>To be added.</summary>
+        <summary>A named reference in a regular expression is malformed.</summary>
       </Docs>
     </Member>
     <Member MemberName="MalformedUnicodePropertyEscape">
@@ -334,7 +342,7 @@
       </ReturnValue>
       <MemberValue>4</MemberValue>
       <Docs>
-        <summary>To be added.</summary>
+        <summary>A Unicode property escape is malformed.</summary>
       </Docs>
     </Member>
     <Member MemberName="MissingControlCharacter">
@@ -354,7 +362,7 @@
       </ReturnValue>
       <MemberValue>7</MemberValue>
       <Docs>
-        <summary>To be added.</summary>
+        <summary>A control character in a regular expression is missing.</summary>
       </Docs>
     </Member>
     <Member MemberName="NestedQuantifiersNotParenthesized">
@@ -374,7 +382,7 @@
       </ReturnValue>
       <MemberValue>28</MemberValue>
       <Docs>
-        <summary>To be added.</summary>
+        <summary>Repeated quantifiers on another quantifier inside a regular expression are not grouped in parentheses.</summary>
       </Docs>
     </Member>
     <Member MemberName="QuantifierAfterNothing">
@@ -394,7 +402,7 @@
       </ReturnValue>
       <MemberValue>29</MemberValue>
       <Docs>
-        <summary>To be added.</summary>
+        <summary>A quantifier in a regular expression is in a position where it cannot quantify anything, like at the beginning of a regular expression or in a group.</summary>
       </Docs>
     </Member>
     <Member MemberName="QuantifierOrCaptureGroupOutOfRange">
@@ -414,7 +422,7 @@
       </ReturnValue>
       <MemberValue>9</MemberValue>
       <Docs>
-        <summary>To be added.</summary>
+        <summary>A captured group or a quantifier in a regular expression is not within range, that is, it is larger than <see cref="F:System.Int32.MaxValue" />.</summary>
       </Docs>
     </Member>
     <Member MemberName="ReversedCharacterRange">
@@ -434,7 +442,7 @@
       </ReturnValue>
       <MemberValue>24</MemberValue>
       <Docs>
-        <summary>To be added.</summary>
+        <summary>A character class in a regular expression contains an inverse character range, like z-a instead of a-z.</summary>
       </Docs>
     </Member>
     <Member MemberName="ReversedQuantifierRange">
@@ -454,7 +462,7 @@
       </ReturnValue>
       <MemberValue>27</MemberValue>
       <Docs>
-        <summary>To be added.</summary>
+        <summary>A quantifier range in a regular expression is inverse, like <code>{10,1}</code> instead of <code>(1,10}</code>.</summary>
       </Docs>
     </Member>
     <Member MemberName="ShorthandClassInCharacterRange">
@@ -474,7 +482,7 @@
       </ReturnValue>
       <MemberValue>25</MemberValue>
       <Docs>
-        <summary>To be added.</summary>
+        <summary>A character-class in a regular expression contains a short-hand class that is not allowed inside a character class.</summary>
       </Docs>
     </Member>
     <Member MemberName="UndefinedNamedReference">
@@ -494,7 +502,7 @@
       </ReturnValue>
       <MemberValue>10</MemberValue>
       <Docs>
-        <summary>To be added.</summary>
+        <summary>A used named reference in a regular expression is not defined.</summary>
       </Docs>
     </Member>
     <Member MemberName="UndefinedNumberedReference">
@@ -514,7 +522,7 @@
       </ReturnValue>
       <MemberValue>11</MemberValue>
       <Docs>
-        <summary>To be added.</summary>
+        <summary>A used numbered reference in a regular expression is not defined.</summary>
       </Docs>
     </Member>
     <Member MemberName="UnescapedEndingBackslash">
@@ -534,7 +542,7 @@
       </ReturnValue>
       <MemberValue>13</MemberValue>
       <Docs>
-        <summary>To be added.</summary>
+        <summary>A regular expression ends with a non-escaped ending backslash.</summary>
       </Docs>
     </Member>
     <Member MemberName="Unknown">
@@ -554,7 +562,7 @@
       </ReturnValue>
       <MemberValue>0</MemberValue>
       <Docs>
-        <summary>To be added.</summary>
+        <summary>An unknown regular expression parse error.</summary>
       </Docs>
     </Member>
     <Member MemberName="UnrecognizedControlCharacter">
@@ -574,7 +582,7 @@
       </ReturnValue>
       <MemberValue>6</MemberValue>
       <Docs>
-        <summary>To be added.</summary>
+        <summary>A control character in a regular expression is not recognized.</summary>
       </Docs>
     </Member>
     <Member MemberName="UnrecognizedEscape">
@@ -594,7 +602,7 @@
       </ReturnValue>
       <MemberValue>5</MemberValue>
       <Docs>
-        <summary>To be added.</summary>
+        <summary>An escape character or sequence in a regular expression is invalid.</summary>
       </Docs>
     </Member>
     <Member MemberName="UnrecognizedUnicodeProperty">
@@ -614,7 +622,7 @@
       </ReturnValue>
       <MemberValue>31</MemberValue>
       <Docs>
-        <summary>To be added.</summary>
+        <summary>A unicode property in a regular expression is not recognized, or invalid.</summary>
       </Docs>
     </Member>
     <Member MemberName="UnterminatedBracket">
@@ -634,7 +642,7 @@
       </ReturnValue>
       <MemberValue>22</MemberValue>
       <Docs>
-        <summary>To be added.</summary>
+        <summary>A regular expression has a non-escaped left square bracket, or misses a closing right square bracket.</summary>
       </Docs>
     </Member>
     <Member MemberName="UnterminatedComment">
@@ -654,7 +662,7 @@
       </ReturnValue>
       <MemberValue>14</MemberValue>
       <Docs>
-        <summary>To be added.</summary>
+        <summary>A comment in a regular expression is not terminated.</summary>
       </Docs>
     </Member>
   </Members>
diff --git a/xml/System.Text.RegularExpressions/RegexParseException.xml b/xml/System.Text.RegularExpressions/RegexParseException.xml
index 12d6ddfacb7..c6ce884abd4 100644
--- a/xml/System.Text.RegularExpressions/RegexParseException.xml
+++ b/xml/System.Text.RegularExpressions/RegexParseException.xml
@@ -14,7 +14,7 @@
   </Base>
   <Interfaces />
   <Docs>
-    <summary>To be added.</summary>
+    <summary>An exception as a result of a parse error in a regular expression, with detailed information in the <see cref="P:System.Text.RegularExpressions.RegexParseException.Error" /> and <see cref="P:System.Text.RegularExpressions.RegexParseException.Offset" /> properties.</summary>
     <remarks>To be added.</remarks>
   </Docs>
   <Members>
@@ -34,9 +34,8 @@
         <ReturnType>System.Text.RegularExpressions.RegexParseError</ReturnType>
       </ReturnValue>
       <Docs>
-        <summary>To be added.</summary>
-        <value>To be added.</value>
-        <remarks>To be added.</remarks>
+        <summary>Gets the error that happened during parsing.</summary>
+        <value>The error that occured during parsing.</value>
       </Docs>
     </Member>
     <Member MemberName="GetObjectData">
@@ -59,10 +58,11 @@
         <Parameter Name="context" Type="System.Runtime.Serialization.StreamingContext" />
       </Parameters>
       <Docs>
-        <param name="info">To be added.</param>
-        <param name="context">To be added.</param>
-        <summary>To be added.</summary>
-        <remarks>To be added.</remarks>
+        <param name="info">The object that holds the serialized object data.</param>
+        <param name="context">The contextual information about the source or destination.</param>
+        <summary>Sets the <paramref name="info" /> object with the parameter name and additional exception information.</summary>
+        <exception cref="T:System.ArgumentNullException">
+          <paramref name="info" /> is <see langword="null" />.</exception>
       </Docs>
     </Member>
     <Member MemberName="Offset">
@@ -81,9 +81,8 @@
         <ReturnType>System.Int32</ReturnType>
       </ReturnValue>
       <Docs>
-        <summary>To be added.</summary>
-        <value>To be added.</value>
-        <remarks>To be added.</remarks>
+        <summary>Gets the zero-based character offset in the regular expression pattern where the parse error occurs.</summary>
+        <value>The offset at which the parse error occurs.</value>
       </Docs>
     </Member>
   </Members>