Another free book out there, every week those guys release a chapter of their books, at the end the books will be available in a single PDF file.
“Ron, Mike and I have decided to start giving away free chapters of our VMware Infrastructure 3: Advanced Technical Design Guide book. This page will be constantly updated every few week or so with 2 new chapters for download. After significant praise about the quality of the book, and significant criticism for its overall size, we figure it is only fair that we provide the book in PDF format so everyone can easily enjoy it regardless of where they are. Once we have provided all chapters for free, we will provide the entire book in a single PDF file.”
Get the chapters here