I would’nt waste your money tbh! All the so called sugar developer books are totally rubbish. I looked at them all when first starting out developing on sugar and the only one which was of some use was The Definitive Guide to SugarCRM by John Mertic and even then it was still very poor.
The truth is Sugar dont really want people being able to easily learn how to develop and expand sugarCRM. You have to be a fairly experanced PHP developer and just try to figure out how things work by looking at the various blogs and forum posts out their. Its a huge beast of an application and has been reworked and expanded many times and as such the back end it a bit confusing at first.
This example here in my blog should show you how to add javascript to a module view that you can then use to make one field disabled until a certain value is selected in another dropdown field.