Inside Lightroom 2 - For users who have upgraded to Lightroom 2, this book is the ticket. With Version 1 under your belt, the upgraded version contains improved features which will come in handy with your workflow.
The value of this book is that it teaches you things you might not know about Lightroom. It covers sophisticated calibration techniques, helping you render your pictures accurately both onscreen and in print. If you know the basics of Lightroom, this book takes you to the next level. It's not a rehashing of what you already know but a bridge to more advanced and comprehensive techniques.