The book begins with an introduction to what makes Knockout work. You're introduced to the Model-View-ViewModel design pattern, observables, and bindings that Knockout uses for keeping track of data and dependencies in your page. You’re then guided through the creation of an obligatory "Hello World!" application. The body of the book is spent examining the various bindings in the Knockout API: control-flow bindings for controlling how your ViewModel is displayed in a view, appearance bindings for changing HTML elements under certain conditions, and interactive bindings for managing user input. The final chapters of the book offer guidance on accessing external data and animating your UI by using Knockout in conjunction with jQuery.
You probably recognize the name Ryan Hodson from two previous entries in the Succinctly series. He wrote Git Succinctly and PDF Succinctly, so with Knockout.js Succinctly, you know what to expect: clear, thorough explanations of topics, vivid diagrams to help you digest those abstract concepts, and code samples that stick to the point.