That depends on what level of book, and what you want to learn from it. On "how real distributed systems are built", there isn't a really good book available in

That depends on what level of book, and what you want to learn from it. On "how real distributed systems are built", there isn't a really good book available in my opinion. I liked The Datacenter as a Computer, but it's scope is fairly narrow and is more focused on global infrastructure issues than software design issues. On the math behind distributed systems, Nancy Lynch's book Distributed Algorithms (http://www.amazon.com/Distributed-Algorithms-Kaufmann-Management-Systems/dp/1558603484 http://www.amazon.com/Distributed-Algorithms-Kaufmann-Manage...) is my favorite, but it's getting to be quite out-of-date. Absent a book, there are a lot of great resources online. High Scalability(http://highscalability.com/ http://highscalability.com/) has a good amount of quality links to distributed systems content, and some editorial content of varying quality. In general, it's a good site to follow if you're interested in how distributed systems are being used in industry. I also like to follow Aphyr's blog(http://aphyr.com/ http://aphyr.com/), Daniel Abadi's blog(http://dbmsmusings.blogspot.com/ http://dbmsmusings.blogspot.com/), and Henry Robinson's blog(http://the-paper-trail.org/blog/ http://the-paper-trail.org/blog/) and Peter Bailis's blog(http://www.bailis.org/ http://www.bailis.org/).