Disclaimer - I haven't purchased this book - I was sent a copy to review by the publisher.
Force.com Tips and Tricks is written by a couple of my fellow Force.com MVPs, Abhinav Gupta and Ankit Arora. It is aimed at both developers and administrators and packs a lot of information into the 200+ pages.
Administrators get a whole chapter dedicated to tools to make their lives easier, including those that come with the platform as standard (e.g. data loader) and a long list of code share and app exchange packages. There is also a deep dive on Salesforce analytics, covering topics such as custom report types, adding formulae to a report and setting up analytic snapshots - all of which are important for administrators wanting to get the most of the platform.
The book starts off with an introduction to the Force.com platform, covering key concepts for anyone starting out with Force.com development such as multi-tenancy, the metadata driven development model and governor limits. Later chapters take you through setting up development environments and migrating changes between those environments, useful tools for developers from both Salesforce and the wider community, and concludes with a couple of chapters that give great advice on writing flexible and scalable Apex and Visualforce code, as well as tips for troubleshooting when code isn't performing as expected.
For administrators wanting to understand more about maintaining and extending Force.com applications, the developer specific sections will prove very useful. By the same token, development in Force.com starts with clicks rather than code, so the administrator-centric chapters are something that every developer should read.
This book isn't a training manual for Force.com development - where I think it would have been really useful in the past was as I was starting to carry out serious development with the platform. I understood enough about the basics to start being productive, but when I was trying something new, I'd be searching the discussion boards and reading blogs to get more information. With a book like this to hand I'd either have the information that I required right there, or be pointed in the right direction to find out more with minimal effort.
I always hope to learn something I didn't know from these books, and this time it was a number of the tools available, particularly to enforce CRUD and FLS when running in the system context. Its certainly a useful addition to my Salesforce library and one I'm sure I'll be coming back to regularly.