For sometime I have wanted to write a Qt book that covered topics that were too advanced for C++ GUI Programming with Qt 4, even though that book itself has proved quite challenging for some readers. There is also some specialized material - not all of it difficult that I wanted to cover that simply does not belong in a first book on Qt programming. Furthermore, in view of the sheer size of Qt, no one book can possibly do justice to all that it offers, so there was clearly room for the presentation of new material.