The author has assembled a collection of code used for games in a library called GameQuery which is available from his website. The text uses inline code samples and does a good job of defining code where it is used, rather than force the reader to grab the source or take it on faith.
Unfortunately, web technology is a fast moving target, and any written book is going to be, by definition, behind the curve. Great technical books can and do exist, and one of their strengths come from the timeless lessons they weave into their material.
Fortunately, some of the content Arsever covers does exactly that. Unfortunately, the remainder consists of an uneven treatment of a very broad grab bag of topics, leaving a beginner - the intended target audience for this book - lost and apt to augment their knowledge with online resources.
The bulk of Chapters 4 and 5 focus on tile-maps for use in building a top-down, RPG style game. The code written in the earlier chapters is augmented here. Arserver really dives deep on this topic, fleshing out the issues related to placing tiles, enemies, interactions between the player and non-playing characters, et cetera. He concludes the chapter with a small discursion on isometric tile systems, points out some challenges but then quickly hurries on to what feels like more comfortable terrain.
Chapter 6 introduces the use of jQuery's AJAX support for asynchronous loading of game data. With this technique, he demonstrates loading tile maps on demand (similar to how Google Maps works) as well as loading other game script resources.
Chapter 9 deals with designing content for mobile browsers, an important consideration for today's web offerings. Important rules-of-the-road are discussed, such as the limited memory, CPU cycles, and rigidity of the browser implementations. Other than cautioning developers, the author offers no concrete suggestions for dealing with mobile performance shortcomings.
The final chapter deals with audio, a critical piece of a game experience. The current state of the art for playing audio in the browser is brittle, and the author readily acknowledges this. Some means for mitigating the lack of a robust solution in the browser, such as using a tag or the Adobe Flash player are mentioned. The HTML5 <audio> tag is mentioned, and a lengthy discussion of the Web Audio API is presented. It is clear that Arserver thinks it is the future, but it would be nice to see practical examples of audio playback with today's crop of browsers. For instance, games often coordinate animation with audio in a seamless fashion that requires low-latency playback. How can a developer accomplish this in today's browsers?
jQuery Game Development Essentials is an ambitious book in scope. A lot of ground is covered, which ultimately dilutes its message. jQuery is used for comparatively little of the book's examples; it's primary uses are for inserting and removing nodes from the DOM, altering CSS, and invoking XmlHttpRequests. That's a lot, and jQuery shines for these tasks, but there is a lot more that framework can do. Coupled with some of the excellent third-party plugins that exist, a lot of the book's code could be simplified.
While some of the writing contained awkwardly phrased English and some slight inaccuracies, the tone and style were easy to follow and kept the reader engaged. Although experienced programmers might find little new here, this book nevertheless is a decent introduction to game development on the web.