The ITK Software Guide is an extensive handbook for image analysis with the Insight Toolkit. Based on the principle of teaching by example, the two books guide the reader through an extensive set of image processing, registration and segmentation methods implemented with the Insight Toolkit. Sections presents a series of examples with associated source code applied to particular image processing and analysis tasks. Fundamental concepts including system architecture, smart pointers and memory management, iterators, and data flow are also described in detail. For those getting started, there is an excellent section on configuring and building ITK.
The Software Guide in now available in HTML for both the first book and the second book. The HTML version is the best form of consumption when reading with a web browser, and the content can be indexed by search engines. For those that want to take an in depth look, the books are also available in hard copy and PDF form.