The heart of Site Server is the Personalization and Membership feature set. This feature allows you to provide personalized content based on user choices as well as secure the content in a membership section of your web site. Wrox's Professional Site Server 3.0 Personalization and Membership book provides information about the Personalization and Membership feature set.
Most technical books take either a programming or implementation slant.
This book covers the whole range. Rob Howard's book takes the Personalization and Membership features of Site Server one step at a time. He is careful to cover the features from installation all the way to programmability. The book uses scenarios to explain the different options including why and when you would want to use them. Rob handles this brilliantly.