A sample chapter is available free from InformIT—click "Sample Content" and then "Download the sample pages".
This 550 page book is aimed at existing C++/Qt programmers and presents ideas and techniques that are too advanced or specialized (although not necessarily difficult), for a first book on Qt.
Qt has now grown to over 700 classes and well over a million words of documentation, far too much to cover in a single volume. So instead of covering everything very thinly, the book focuses on key areas of Qt technology and tries to provide more comprehensive coverage than is available elsewhere.
The book is completely practical in emphasis, with every technique illustrated by working code. The examples show Qt best practices. They have been tested on Linux, Mac OS X, and Windows, using Qt 4.6, and where possible (e.g., using #if QT_VERSION), Qt 4.5. In addition they have been tested on Linux using Qt 4.8 and Qt 4.7 (which versions should also be fine for Mac OS X and Windows).
The book's main themes are hybrid desktop/Internet applications, threading, rich text handling, Qt's graphics/view architecture, and Qt's model/view architecture (to which four chapters are devoted), although many other topics are covered. Besides each chapter's main subject, lots of other classes, methods, and techniques are used wherever they make sense, to show as many Qt features as possible. So even the most experienced Qt programmer should discover aspects of Qt they weren't aware of, discover new techniques, and be inspired with new ideas.
The book can be bought from Amazon.com, Amazon.co.uk, and other online and local book stores.
Only the printed editions in English are definitive—although available in electronic formats, "ebooks" usually restrict your rights, and they are often retypeset which can introduce errors. A legal PDF version is available from InformIT. Translations are arranged by the publisher and their quality can vary considerably.
The source code is available in two formats, aqpbook.tar.gz (1.2MB suitable for any platform), and aqpbook.zip (1.3MB Windows line endings) [updated 2011-02-21]. The source code includes the Alt_Key library. There is also an Errata [updated 2014-01-06]. Walter Dale has ported almost all of the book's examples to Qt 5— aqp-qt5-eg.zip (2.8MB, including some porting notes in the archive's file aqp-qt5/aqp-qt5-eg-notes.html).
For more information on Qt see Qt Development Frameworks.
Like all my books and most of my other writings, this book was written using The Lout Typesetting System.