This is a collection of essays by different authors on introductory-level aspects on cloud computing. Very little editing has gone on, so there is a lot of overlap in the first few sections and it can get a bit monotonous. However, this is maybe not a bad thing if you just wanted to get a feel for the landscape and terminology. The best part of the book is the last section, which tackles security and legal aspects. This part is quite detailed, where the earlier parts of the book seem to involve quite a bit of vague hand-waving.
I would have liked to have seen more on the API/mashup aspect of Cloud Computing, since adding value through consuming different services seems to me a rather powerful opportunity which is not discussed here. Rather, the text focuses on the more mainstream aspects of cloud-based storage, applications and databases, and the rather obvious advantages of saving money by buying less server infrastructure and fewer software licences yourself.
In summary, not a bad introductory read if you just want to get a feel for the jargon and the issues. It's exceptionally cheap for Kindle and probably takes less than 2 hours to read, so the investment to really low for some useful content. Buy it and skim-read for the best bits.