diff --git a/cpdfannot.mli b/cpdfannot.mli
index a25711a..cc76d26 100644
--- a/cpdfannot.mli
+++ b/cpdfannot.mli
@@ -1,4 +1,4 @@
-(** {2 Annotations} *)
+(** Annotations *)
 
 (** List the annotations to standard output in a given encoding. See cpdfmanual.pdf for the format details. *)
 val list_annotations : json:bool -> Cpdfmetadata.encoding -> Pdf.t -> unit
diff --git a/cpdfcommand.ml b/cpdfcommand.ml
index 7770e1c..fd7f09f 100644
--- a/cpdfcommand.ml
+++ b/cpdfcommand.ml
@@ -3,7 +3,7 @@ let demo = false
 let noncomp = false
 let major_version = 2
 let minor_version = 5
-let version_date = "(9th Jan 2022)"
+let version_date = "(14th Jan 2022)"
 
 open Pdfutil
 open Pdfio
diff --git a/cpdfimpose.mli b/cpdfimpose.mli
index 2608596..605fcb1 100644
--- a/cpdfimpose.mli
+++ b/cpdfimpose.mli
@@ -1,12 +1,13 @@
-(** {2 Imposition} *)
+(** Imposition *)
 
+(** Imposition. See cpdfmanual.pdf for details. *)
 val impose : x:float -> y:float -> fit:bool -> columns:bool -> rtl:bool -> btt:bool -> center:bool -> margin:float -> spacing:float -> linewidth:float -> fast:bool -> Pdf.t -> Pdf.t
 
-(** The twoup_stack operation puts two logical pages on each physical page,
+(** The legacy twoup_stack operation puts two logical pages on each physical page,
 rotating them 90 degrees to do so. The new mediabox is thus larger. Bool true
 (fast) if assume well-formed ISO content streams. *)
 val twoup_stack : bool -> Pdf.t -> Pdf.t
 
-(** The twoup operation does the same, but scales the new sides down so that
+(** The legacy twoup operation does the same, but scales the new sides down so that
 the media box is unchanged. Bool true (fast) if assume well-formed ISO content streams. *)
 val twoup : bool -> Pdf.t -> Pdf.t
diff --git a/cpdfocg.mli b/cpdfocg.mli
index 8d13d01..9b2c89a 100644
--- a/cpdfocg.mli
+++ b/cpdfocg.mli
@@ -1,9 +1,16 @@
-val ocg_coalesce : Pdf.t -> unit
+(** Optional content groups *)
 
+(** Return list of OCG names. *)
 val ocg_get_list : Pdf.t -> string list
 
+(** Print OCG list to Standard Output. *)
 val ocg_list : Pdf.t -> unit
 
+(** Coalesce same-named OCGs resulting from merge. *)
+val ocg_coalesce : Pdf.t -> unit
+
+(** Rename an OCG. *)
 val ocg_rename : string -> string -> Pdf.t -> unit
 
+(** Make sure every OCG is in the /Order. *) 
 val ocg_order_all : Pdf.t -> unit
diff --git a/cpdfpad.mli b/cpdfpad.mli
index ba599a0..f9a4b3e 100644
--- a/cpdfpad.mli
+++ b/cpdfpad.mli
@@ -1,4 +1,4 @@
-(** {2 Padding} *)
+(** Padding *)
 
 (** Put blank pages before the given page numbers *)
 val padbefore : ?padwith:Pdf.t -> int list -> Pdf.t -> Pdf.t
diff --git a/cpdfpage.mli b/cpdfpage.mli
index a9fbf3b..e9dfad4 100644
--- a/cpdfpage.mli
+++ b/cpdfpage.mli
@@ -1,4 +1,4 @@
-(** {2 Working with pages} *)
+(** Working with pages *)
 
 (** Print page info (Mediabox etc) to standard output. *)
 val output_page_info : Pdf.t -> int list -> unit
@@ -14,14 +14,22 @@ val iter_pages : (int -> Pdfpage.t -> unit) -> Pdf.t -> int list -> unit
 (** Same as [process_pages] but return the list of outputs of the map function. *)
 val map_pages : (int -> Pdfpage.t -> 'a) -> Pdf.t -> int list -> 'a list
 
+(** Clip a page to one of its boxes, or the media box if that box is not
+ present. This is a hard clip, done by using a clipping rectangle, so that the
+ page may then be used as a stamp without extraneous material reapearing. *)
 val hard_box : Pdf.t -> int list -> string -> bool -> bool -> Pdf.t
 
 (** Shift a PDF in x and y (in pts) in the given pages. List of (x, y) pairs is
 for all pages in pdf. *)
 val shift_pdf : ?fast:bool -> (float * float) list -> Pdf.t -> int list -> Pdf.t
 
+(** Change a page's media box so its minimum x and y are 0, making other
+operations simpler to think about. Any shift that is done is reflected in
+other boxes (clip etc.) *)
 val rectify_boxes : ?fast:bool -> Pdf.t -> Pdfpage.t -> Pdfpage.t
 
+(** Change the media box and other known boxes by a function which takes
+xmin, xmax, ymin, ymax as input. *)
 val change_boxes : (float * float * float * float -> float * float * float * float) ->
            Pdf.t -> Pdfpage.t -> Pdfpage.t 
 
@@ -98,10 +106,14 @@ val vflip_pdf : ?fast:bool -> Pdf.t -> int list -> Pdf.t
 (** Flip the given pages horizontally *)
 val hflip_pdf : ?fast:bool -> Pdf.t -> int list -> Pdf.t
 
+(** Add trim marks. *)
 val trim_marks : ?fast:bool -> Pdf.t -> int list -> Pdf.t
 
+(** Show the page boxes for debug. *)
 val show_boxes : ?fast:bool -> Pdf.t -> int list -> Pdf.t
 
+(** Copy one box to another in the given pages. *)
 val copy_box : string -> string -> bool -> Pdf.t -> int list -> Pdf.t
 
+(** True if all pages are "upright" i.e no rotation and (0,0)-based. *)
 val allupright : int list -> Pdf.t -> bool
diff --git a/cpdfpagelabels.mli b/cpdfpagelabels.mli
index 3083233..9146940 100644
--- a/cpdfpagelabels.mli
+++ b/cpdfpagelabels.mli
@@ -1,6 +1,5 @@
-(** {2 Page labels} *)
+(** Page labels *)
 
 (** Add page labels. *)
 val add_page_labels :
   Pdf.t -> bool -> Pdfpagelabels.labelstyle -> string option -> int -> int list -> unit 
-
diff --git a/cpdfspot.mli b/cpdfspot.mli
index 2c11426..7b4b263 100644
--- a/cpdfspot.mli
+++ b/cpdfspot.mli
@@ -1 +1,4 @@
+(** Spot colours *)
+
+(** List spot colours to Standard Output. *)
 val list_spot_colours : Pdf.t -> unit
diff --git a/cpdfsqueeze.mli b/cpdfsqueeze.mli
index b2d42d4..e532f6f 100644
--- a/cpdfsqueeze.mli
+++ b/cpdfsqueeze.mli
@@ -1,3 +1,5 @@
+(** Lossless compression *)
+
 (** Compresses all streams in the PDF document which are uncompressed, using
 /FlateDecode, leaving out metadata.  If the PDF is encrypted, does nothing. *)
 val recompress_pdf : Pdf.t -> Pdf.t
diff --git a/cpdftoc.mli b/cpdftoc.mli
index 7e8e6c3..9f749a5 100644
--- a/cpdftoc.mli
+++ b/cpdftoc.mli
@@ -1 +1,4 @@
+(** Table of contents *)
+
+(** Typeset a table of contents and prepend to the document. *)
 val typeset_table_of_contents : font:Pdftext.standard_font -> fontsize:float -> title:string -> bookmark:bool -> Pdf.t -> Pdf.t