This is a review of the 2nd edition. It's a good book but could be improved by including more detail on OSX and Windows with some links to graphical tools.
An easy read and makes a lot of sense for someone with existing version control knowledge (Subversion, CVS etc.).
If you are starting from scratch and have not used source control before then you’ll find all the new concepts too overwhelming. That’s not an issue with the book, it’s just not pitched at the beginner level.
The content is primarily focused on the Linux tools but that’s not a problem as these have all been ported to the other platforms (client installation is covered early on). Because of this Linux focus the graphical tools are not shown which would be an easier way in for non-command line oriented developers. To get a decent understanding of Git I’m going to be using the command line for a month anyway.
My (minor) gripes over with, I would really recommend this book is used as a training aid, working through a chapter every day perhaps (some chapters are heavy or can be skimmed, you can always come back to them later). New concepts and terminology are covered well which is really useful as I’d no idea what Stash, Rebase and Reflog were about.
If I could have a wishlist for the 3rd edition it would be to include chapters on both Windows and OSX, plus a chapter on the top rated graphical clients.
In summary, buy this book. If you are new to source control or just don’t like the command line, supplement it with a decent graphical toolset such as TortoiseGit (you can find tons of them for most platforms at http://git-scm.com/downloads/guis and http://delicious.com/matthew.mccullough/git+gui).