I had often heard Cal Newport's take on work and passion referred to in the forums, and was familiar with his ideas in general, so was interested in reading the book version.
Overall, I found it well worth reading (possibly because I have accidentally been doing a lot that Newport recommends...always nice to be agreed with!) Although a lot of it is directed at people at the beginning of their careers, I thought the section on deliberate practice was very interesting and worth some thought even for a mid-career person. I would definitely give it to a younger person trying to figure out their work life.
Anyway, I recommend taking a look...it is a quick and easy read. I finished it in a couple of hours.