Tag clouds are all good and nice, but I personally always liked looking at an index of a book. It gives every book a structured clean look and feel. There is also the advantage of finding things you didnt know you were looking for. The first step of every search is finding the right terminology to find what you are looking for. An index can often be of great help and guide you in the right direction.
To get you started, go download the plugin, activate it and than use the following short code where you want your index:
[ mctagmap columns="3" more="- show all -" hide="yes" num_show="5" toggle="- hide -" show_empty="no" ]
To find more information about Multi-column Tag Map, visit tugbucket.net/wordpress/wordpress-plugin-multi-column-tag-map/