Many of us have good collection of e-books in chm format, here is a small software that enables us to view chm files in Ubuntu
How to install gnochm in ubuntu
Open your terminal and type sudo apt-get install gnochm to install gnochm (make sure you have an active internet connection).
How to Open gnochm
To open GnoCHM go to Applications->Accessories->CHM Viewer
Official site of gnochm
download your copy of gnochm