diff --git a/docs/latex/wx/hthelpct.tex b/docs/latex/wx/hthelpct.tex
index aa79aec117..f7a1378b5b 100644
--- a/docs/latex/wx/hthelpct.tex
+++ b/docs/latex/wx/hthelpct.tex
@@ -60,6 +60,11 @@ Default value : everything enabled.
 Adds book (\helpref{.hhp file}{helpformat} - HTML Help Workshop project file) into the list of loaded books.
 This must be called at least once before displaying  any help.
 
+{\it book} may be either .hhp file or ZIP archive that contains arbitrary number of .hhp files in 
+top-level directory. This ZIP archive must have .zip or .htb extension
+(the latter stands for "HTML book"). In other words, {\tt AddBook("help.zip")} is possible and, in fact,
+recommended way.
+
 If {\it show\_wait\_msg} is TRUE then a decorationless window with progress message is displayed.
 
 \membersection{wxHtmlHelpController::Display}\label{wxhtmlhelpcontrollerdisplay}