> There is a site.
> Books
> are in files like www.aaa.bb/b_something.html
> www.aaa.bb/forum
> www.aaa.bb/something_else
> I want do download a part of site. Only books.
> I give as start URL for WinHTTrack this one :
> www.aaa.bb/books.html

Either use filters (scan rules), or use:
-*
.. and use Set Options/Links/"Get non-html files related to 
a link" to fetch the "books" if they are non-html files 
(such as pdf's)