diff --git a/cpdfattach.mli b/cpdfattach.mli
index 58b6c7b..4e32872 100644
--- a/cpdfattach.mli
+++ b/cpdfattach.mli
@@ -1,18 +1,24 @@
-(** {2 File Attachments} *)
-val remove_unsafe_characters : Cpdfmetadata.encoding -> string -> string
-
-(** [attach_file keepversion topage pdf filename] attaches the file in [filename] to the pdf, optionally to a page (rather than document-level). If keepversion is true, the PDF version number won't be altered. *)
-val attach_file : ?memory:Pdfio.bytes -> bool -> int option -> Pdf.t -> string -> Pdf.t
-
-(** Remove attached files. *)
-val remove_attached_files : Pdf.t -> Pdf.t
+(** File Attachments *)
 
 type attachment =
   {name : string;
    pagenumber : int;
    data : unit -> Pdfio.bytes}
 
+(** Remove characters which might not make good filenames. If the encoding is
+    [Cpdfmetadata.Stripped] we in addition lose any character > 126. *)
+val remove_unsafe_characters : Cpdfmetadata.encoding -> string -> string
+
+(** [attach_file keepversion topage pdf filename] attaches the file in
+    [filename] to the pdf, optionally to a page (rather than document-level).
+    If keepversion is true, the PDF version number won't be altered. *)
+val attach_file : ?memory:Pdfio.bytes -> bool -> int option -> Pdf.t -> string -> Pdf.t
+
+(** Remove attached files. *)
+val remove_attached_files : Pdf.t -> Pdf.t
+
 (** List attached files. Attachment name and page number. Page 0 is document level. *)
 val list_attached_files : Pdf.t -> attachment list
 
+(** Dump attached files to a given directory. *)
 val dump_attached_files : Pdf.t -> string -> unit
diff --git a/cpdfbookmarks.ml b/cpdfbookmarks.ml
index 29038b5..1d6cef8 100644
--- a/cpdfbookmarks.ml
+++ b/cpdfbookmarks.ml
@@ -413,4 +413,3 @@ let change_destination t = function
 let change_bookmark t m =
   {m with Pdfmarks.target =
     try change_destination t m.Pdfmarks.target with Not_found -> m.Pdfmarks.target}
-
diff --git a/cpdfbookmarks.mli b/cpdfbookmarks.mli
index 7772c0c..79723ba 100644
--- a/cpdfbookmarks.mli
+++ b/cpdfbookmarks.mli
@@ -1,24 +1,33 @@
-(** {2 Bookmarks} *)
+(** Bookmarks *)
 
 (** [parse_bookmark_file verify pdf input] parses the bookmark file in [input].
-Details of the bookmark file format can be found in cpdfmanual.pdf *)
+Details of the bookmark file format can be found in cpdfmanual.pdf. *)
 val parse_bookmark_file : bool -> Pdf.t -> Pdfio.input -> Pdfmarks.t list
 
 (** [add_bookmarks verify input pdf] adds bookmarks from the bookmark file
 give. If [verify] is given, bookmarks will be verified to ensure, for example,
-that they are not out of the page range. *) 
+that they are not out of the page range. In the new JSON format if chosen. *) 
 val add_bookmarks : json:bool -> bool -> Pdfio.input -> Pdf.t -> Pdf.t
 
 (** [list_bookmarks encoding range pdf output] lists the bookmarks to the given
-output in the format specified in cpdfmanual.pdf *)
+output in the format specified in cpdfmanual.pdf. In the new JSON format if
+chosen. *)
 val list_bookmarks : json:bool -> Cpdfmetadata.encoding -> int list -> Pdf.t -> Pdfio.output -> unit
 
+(** [name_of_spec encoding marks pdf splitlevel spec n filename startpage
+    endpage] expands a bookmark specifiation filename. *)
 val name_of_spec : Cpdfmetadata.encoding ->
            Pdfmarks.t list ->
            Pdf.t -> int -> string -> int -> string -> int -> int -> string
 
+(** Indent bookmarks in each file by one and add a title bookmark pointing to
+   the first page. If the boolean is set, then use the PDF's metadata title
+   instead of the filename. *)
 val add_bookmark_title : string -> bool -> Pdf.t -> Pdf.t
 
+(** Set bookmarks to be open to the given level. *) 
 val bookmarks_open_to_level : int -> Pdf.t -> Pdf.t
 
+(** Alter bookmark destinations given a hash table of (old page reference
+number, new page reference number) pairings *)
 val change_bookmark : (int, int) Hashtbl.t -> Pdfmarks.t -> Pdfmarks.t 
diff --git a/cpdfcoord.mli b/cpdfcoord.mli
index aef004a..af096a6 100644
--- a/cpdfcoord.mli
+++ b/cpdfcoord.mli
@@ -1,8 +1,15 @@
-(* Parsing coordinates, numbers, positions etc. *)
+(** Parsing coordinates, numbers, positions etc.*)
+
+(** See cpdfmanual.pdf for examples of things these functions can parse, such as page sizes. *)
+
+(** Read a list of rectangles from a string. *)
 val parse_rectangles : Pdf.t -> string -> (float * float * float * float) list
 
+(** Read a coordinate from a string *)
 val parse_coordinate : Pdf.t -> string -> float * float
 
+(** Read a list of coordinates from a string *)
 val parse_coordinates : Pdf.t -> string -> (float * float) list
 
+(** Read a single number from a string *)
 val parse_single_number : Pdf.t -> string -> float
diff --git a/cpdfmetadata.mli b/cpdfmetadata.mli
index c1ed9ec..4f5081b 100644
--- a/cpdfmetadata.mli
+++ b/cpdfmetadata.mli
@@ -1,3 +1,4 @@
+(** Metadata *)
 
 (** {2 Types and Exceptions} *)
 
@@ -7,6 +8,7 @@ all - the PDF string is output as-is. [UTF8] converts loslessly to UTF8.
 correspond to 7 bit ASCII. *)
 type encoding = Raw | UTF8 | Stripped
 
+(** Encode a string using a given encoding. *) 
 val encode_output : encoding -> string -> string
 
 (** {2 Metadata and settings} *)
@@ -20,6 +22,7 @@ val copy_id : bool -> Pdf.t -> Pdf.t -> Pdf.t
 the PDF minor version to [version].*)
 val set_pdf_info : ?xmp_also:bool -> ?xmp_just_set:bool -> (string * Pdf.pdfobject * int) -> Pdf.t -> Pdf.t
 
+(** Get XMP information for a given key. *)
 val get_xmp_info : Pdf.t -> string -> string
 
 (** [set_pdf_info (key, value, version)] sets the entry [key] in the
@@ -71,4 +74,5 @@ val print_metadata : Pdf.t -> unit
 (** Set the metadata date *)
 val set_metadata_date : Pdf.t -> string -> Pdf.t
 
+(** Expands the date ["now"] to the date now. Leaves any other string alone. *) 
 val expand_date : string -> string
diff --git a/cpdfpagespec.mli b/cpdfpagespec.mli
index 018a4d0..5c4e158 100644
--- a/cpdfpagespec.mli
+++ b/cpdfpagespec.mli
@@ -1,4 +1,4 @@
-(** {2 Page specifications and ranges } *)
+(** Page specifications and ranges *)
 
 (** Here are the rules for building input ranges:
 
diff --git a/cpdfposition.mli b/cpdfposition.mli
index a70cfe1..a38ce3a 100644
--- a/cpdfposition.mli
+++ b/cpdfposition.mli
@@ -1,3 +1,5 @@
+(** Positions *)
+
 (** Possible positions for adding text and other uses. See cpdfmanual.pdf *)
 type position =
     PosCentre of float * float
diff --git a/cpdfpresent.mli b/cpdfpresent.mli
index 2305348..4da6a9f 100644
--- a/cpdfpresent.mli
+++ b/cpdfpresent.mli
@@ -1,8 +1,7 @@
-(** {2 Presentations} *)
+(** Presentations *)
 
 (** [presentation range t d horizontal inward direction effect_duration pdf]
 adds a presentation on the pages in [range]. See cpdfmanual.pdf for details.
 *)
 val presentation : int list -> string option ->
     float option -> bool -> bool -> int -> float -> Pdf.t -> Pdf.t
-