There are many computer books come with CHM format. I like the ability to read these files under my Ubuntu Dapper.
Gnochm is a CHM file viewer. It is designed to integrate nicely with Gnome. Gnochm has some really nice features for viewing chm files.
Screenshot
Gnochm View
Gnochm Applications Menu
Gnochm Engage
Installing Gnochm
sudo apt-get install gnochm
Simply click on the Applications menu in the Accessories section to start Gnochm and open your chm files.
Have a great day and gud lak!