diff --git a/changelog.txt b/changelog.txt
new file mode 100644
--- /dev/null
+++ b/changelog.txt
@@ -0,0 +1,3 @@
+v0.1.0.0 - Initial
+
+v0.1.1.0 - Added the BlockTagContent type
diff --git a/library/pro-abstract/ProAbstract.hs b/library/pro-abstract/ProAbstract.hs
--- a/library/pro-abstract/ProAbstract.hs
+++ b/library/pro-abstract/ProAbstract.hs
@@ -27,7 +27,7 @@
 
 Optics:
 
-- 'tag' targets the tag at a node; it is either a prism or an affine traversal, depending on the node type.
+- 'tag' targets the tag at a node; it is either a lens or an affine traversal, depending on the node type.
 - The 'allTags' traversal targets every tag at and below a node.
 - The 'allBlockTags' and 'allInlineTags' also target tags at or below a node, but are limited to tags at the block or inline level, respectively.
 - Since a tag has metadata, all of the optics for targeting parts of metadata (e.g. 'atSetting' and 'hasProperty') are also available on 'Tag' and on 'Tagged' nodes.
@@ -37,7 +37,9 @@
   - Pure: 'mapMaybeTags', 'mapMaybeBlockTags', 'mapMaybeInlineTags'
   - Monadic: 'witherTags', 'witherBlockTags', 'witherInlineTags'
 
+Example: @'mapMaybeTags' (preview (filtered \\x -> view 'name' x /= "comment"))@ is an endofunction that removes all nodes having a tag name of "comment".
 
+
 === The Block level
 
 /Block-level/ content is everything that appears below the document level and above the paragraph level.
@@ -57,7 +59,7 @@
 
 - /Paragraphs/ contain inline content.
 
-    * 'Paragraph' = ('content' : 'Lines') × ('annotation' : 'Annotation')
+    * 'Paragraph' = ('contents' : 'Line') × ('annotation' : 'Annotation')
 
 Unenforced guideline: The 'Lines' of a 'Paragraph' should contain at least one 'Line'.
 
@@ -74,7 +76,12 @@
 
 Example: @'blockTag' % 'Optics.Core.filtered' (\x -> 'Optics.Core.view' 'name' x == "h1")@ is an affine fold that targets blocks with a tag name of "h1".
 
+The BlockTag type can also be described as:
 
+- 'BlockTag' = ('tag' :: 'Tag') × ('content' : 'BlockTagContent')
+- 'BlockTagContent' = ('fork' : 'Blocks') ∪ ('plain' : 'PlainBlock')
+
+
 === The Inline level
 
 /Inline-level/ content is everything below the paragraph level.
@@ -115,7 +122,7 @@
 
 Optics:
 
-- 'metadata' targets the metadata of a node; it is either a prism or an affine traversal, depending on the node type.
+- 'metadata' targets the metadata of a node; it is either a lens or an affine traversal, depending on the node type.
 - 'atSetting' and 'hasProperty' target specific parts of metadata by name.
 - The 'allMetadata' traversal targets every metadata at and under a node.
 
@@ -134,6 +141,8 @@
 | 'Document'            | 'Blocks'              | 'Block'               |
 +-----------------------+-----------------------+-----------------------+
 | 'Blocks'              | —                     | 'Block'               |
++-----------------------+-----------------------+-----------------------+
+| 'BlockTag'            | 'BlockTagContent'     | —                     |
 +-----------------------+-----------------------+-----------------------+
 | 'Paragraph'           | 'Lines'               | 'Line'                |
 +-----------------------+-----------------------+-----------------------+
diff --git a/library/pro-abstract/ProAbstract/Datatypes.hs b/library/pro-abstract/ProAbstract/Datatypes.hs
--- a/library/pro-abstract/ProAbstract/Datatypes.hs
+++ b/library/pro-abstract/ProAbstract/Datatypes.hs
@@ -4,7 +4,7 @@
       Document (..)
 
     -- * Blocks
-    , Block (..), Blocks (..)
+    , Block (..), Blocks (..), BlockTagContent (..)
 
     -- * Lines
     , Inline (..), Line (..), Lines (..)
diff --git a/library/pro-abstract/ProAbstract/Structure.hs b/library/pro-abstract/ProAbstract/Structure.hs
--- a/library/pro-abstract/ProAbstract/Structure.hs
+++ b/library/pro-abstract/ProAbstract/Structure.hs
@@ -4,7 +4,7 @@
       Document (..)
 
     -- * Blocks
-    , Block (..), paragraph, Blocks (..), BlockTag (..), blockTag
+    , Block (..), paragraph, Blocks (..), BlockTag (..), blockTag, BlockTagContent (..)
 
     -- * Paragraph
     , Paragraph (..)
@@ -29,6 +29,7 @@
 
 import ProAbstract.Structure.Block
 import ProAbstract.Structure.BlockTag
+import ProAbstract.Structure.BlockTagContent
 import ProAbstract.Structure.CanBePlain
 import ProAbstract.Structure.CanFork
 import ProAbstract.Structure.Document
diff --git a/library/pro-abstract/ProAbstract/Structure/BlockTag.hs b/library/pro-abstract/ProAbstract/Structure/BlockTag.hs
--- a/library/pro-abstract/ProAbstract/Structure/BlockTag.hs
+++ b/library/pro-abstract/ProAbstract/Structure/BlockTag.hs
@@ -3,8 +3,10 @@
     ) where
 
 import ProAbstract.Annotation
+import ProAbstract.Content
 import ProAbstract.Metadata
 import ProAbstract.Structure.Block
+import ProAbstract.Structure.BlockTagContent
 import ProAbstract.Structure.CanBePlain
 import ProAbstract.Structure.CanFork
 import ProAbstract.Structure.Fork
@@ -19,11 +21,25 @@
     BlockTagFork  (Tagged (Blocks ann))     -- ^ 'ProAbstract.fork'
   | BlockTagPlain (Tagged (PlainBlock ann)) -- ^ 'ProAbstract.plain'
 
+type instance Content (BlockTag ann) = BlockTagContent ann
+
 type instance Annotation (BlockTag ann) = ann
 
 type instance Plain (BlockTag ann) = Tagged (PlainBlock ann)
 
 type instance Fork (BlockTag ann) = Tagged (Blocks ann)
+
+instance HasContent (BlockTag ann) (BlockTag ann) where
+    content = lens f g
+      where
+        f = \case
+            BlockTagFork x -> BlockTagContent_Fork $ view content x
+            BlockTagPlain x -> BlockTagContent_Plain $ view content x
+        g x = \case
+            BlockTagContent_Fork c -> BlockTagFork $ TaggedBlocks t c
+            BlockTagContent_Plain c -> BlockTagPlain $ TaggedPlainBlock t c
+          where
+            t = view tag x
 
 instance CanFork (BlockTag ann) where
     fork = prism' BlockTagFork \case{ BlockTagFork x -> Just x; _ -> Nothing }
diff --git a/library/pro-abstract/ProAbstract/Structure/BlockTagContent.hs b/library/pro-abstract/ProAbstract/Structure/BlockTagContent.hs
new file mode 100644
--- /dev/null
+++ b/library/pro-abstract/ProAbstract/Structure/BlockTagContent.hs
@@ -0,0 +1,70 @@
+module ProAbstract.Structure.BlockTagContent
+    ( BlockTagContent (..)
+    ) where
+
+import ProAbstract.Annotation
+import ProAbstract.Metadata
+import ProAbstract.Structure.Block
+import ProAbstract.Structure.CanBePlain
+import ProAbstract.Structure.CanFork
+import ProAbstract.Structure.Fork
+import ProAbstract.Structure.HasManyParagraphs
+import ProAbstract.Structure.HasManyPlainBlocks
+import ProAbstract.Structure.HasManyPlainInlines
+import ProAbstract.Structure.Plain
+import ProAbstract.Structure.PlainBlock
+import ProAbstract.Tag
+
+data BlockTagContent ann =
+    BlockTagContent_Fork  (Blocks ann)     -- ^ 'ProAbstract.fork'
+  | BlockTagContent_Plain (PlainBlock ann) -- ^ 'ProAbstract.plain'
+
+type instance Annotation (BlockTagContent ann) = ann
+
+type instance Plain (BlockTagContent ann) = PlainBlock ann
+
+type instance Fork (BlockTagContent ann) = Blocks ann
+
+instance CanBePlain (BlockTagContent ann) where
+    plain = prism' BlockTagContent_Plain \case
+        BlockTagContent_Plain x -> Just x; _ -> Nothing
+
+instance CanFork (BlockTagContent ann) where
+    fork = prism' BlockTagContent_Fork \case
+        BlockTagContent_Fork x -> Just x; _ -> Nothing
+
+instance HasManyPlainBlocks (BlockTagContent ann) where
+    allPlainBlocks = fork % allPlainBlocks
+
+instance HasManyPlainInlines (BlockTagContent ann) where
+    allPlainInlines = fork % allPlainInlines
+
+instance HasManyAnnotations (BlockTagContent ann) (BlockTagContent ann') where
+    allAnnotations = traversalVL \f -> \case
+        BlockTagContent_Fork x -> BlockTagContent_Fork <$> traverseOf allAnnotations f x
+        BlockTagContent_Plain x -> BlockTagContent_Plain <$> traverseOf allAnnotations f x
+
+instance HasManyMetadata (BlockTagContent ann) where
+    allMetadata = fork % allMetadata
+
+instance HasManyTags (BlockTagContent ann) where
+    allTags = fork % allTags
+    allInlineTags = fork % allInlineTags
+
+instance HasManyBlockTags (BlockTagContent ann) where
+    allBlockTags = fork % allBlockTags
+
+instance HasWitherableTags (BlockTagContent ann) where
+    witherTags f = traverseOf fork (witherTags f)
+    mapMaybeTags f = over fork (mapMaybeTags f)
+
+instance HasWitherableInlineTags (BlockTagContent ann) where
+    witherInlineTags f = traverseOf fork (witherInlineTags f)
+    mapMaybeInlineTags f = over fork (mapMaybeInlineTags f)
+
+instance HasWitherableBlockTags (BlockTagContent ann) where
+    witherBlockTags f = traverseOf fork (witherBlockTags f)
+    mapMaybeBlockTags f = over fork (mapMaybeBlockTags f)
+
+instance HasManyParagraphs (BlockTagContent ann) where
+    allParagraphs = fork % allParagraphs
diff --git a/library/pro-abstract/ProAbstract/Tagless/CanBeTagless.hs b/library/pro-abstract/ProAbstract/Tagless/CanBeTagless.hs
--- a/library/pro-abstract/ProAbstract/Tagless/CanBeTagless.hs
+++ b/library/pro-abstract/ProAbstract/Tagless/CanBeTagless.hs
@@ -40,6 +40,9 @@
             % all @Maybe (tagless s) -- If there is a block, it has to be convertable to the desired text kind
             % to (fromMaybe (noText s)) -- If there are no blocks, return an empty line or stanza
 
+instance CanBeTagless (BlockTagContent ann) where
+    tagless s = (fork % tagless s) `afailing` (plain % tagless s)
+
 noText :: KindOfText txt -> txt
 noText = \case{ TextLine -> textEmpty; TextStanza -> Empty; TextParagraphs -> Empty }
 
diff --git a/library/pro-abstract/ProAbstract/Tagless/CanHaveTaglessContent.hs b/library/pro-abstract/ProAbstract/Tagless/CanHaveTaglessContent.hs
--- a/library/pro-abstract/ProAbstract/Tagless/CanHaveTaglessContent.hs
+++ b/library/pro-abstract/ProAbstract/Tagless/CanHaveTaglessContent.hs
@@ -21,6 +21,9 @@
         (plain % taglessContent @(Tagged (PlainBlock ann)) s) `afailing`
         (fork % taglessContent @(Tagged (Blocks ann)) s)
 
+instance CanHaveTaglessContent (BlockTagContent ann) where
+    taglessContent = tagless
+
 instance CanHaveTaglessContent (Inline ann) where
     taglessContent s = (plain % tagless s) `afailing` (fork % taglessContent s)
 
diff --git a/library/pro-abstract/ProAbstract/Types.hs b/library/pro-abstract/ProAbstract/Types.hs
--- a/library/pro-abstract/ProAbstract/Types.hs
+++ b/library/pro-abstract/ProAbstract/Types.hs
@@ -3,6 +3,7 @@
     , Block
     , Blocks
     , BlockTag
+    , BlockTagContent
     , Content
     , Contents
     , Document
diff --git a/pro-abstract.cabal b/pro-abstract.cabal
--- a/pro-abstract.cabal
+++ b/pro-abstract.cabal
@@ -1,7 +1,7 @@
 cabal-version: 3.0
 
 name: pro-abstract
-version: 0.1.0.0
+version: 0.1.1.0
 
 category: Language
 synopsis: Abstract syntax for writing documents
@@ -21,6 +21,8 @@
     © 2020 James Alexander Feldman-Crough,
     © 2022 Mission Valley Software LLC
 
+extra-source-files: changelog.txt
+
 source-repository head
     type: git
     location: git://github.com/typeclasses/pro-abstract.git
@@ -88,6 +90,7 @@
       , ProAbstract.Metadata.MetadataType
       , ProAbstract.Structure.Block
       , ProAbstract.Structure.BlockTag
+      , ProAbstract.Structure.BlockTagContent
       , ProAbstract.Structure.CanBePlain
       , ProAbstract.Structure.CanFork
       , ProAbstract.Structure.Document