I'm a coauthor of How to Build a Beowulf: A Guide to the Implementation and Application of PC Clusters, published by MIT Press. The first printing was published in May 1999, sold out in July, and a second printing hit the stores in late August.
A Japanese translation of the first edition has also been released.
Thomas has finished a second book with an ensemble of collaborators. The new book comes in a Linux flavor and a Windows flavor and contains more comprehensive and advanced material than the first book.