UML 2.0 in a Nutshell (In a Nutshell (O'Reilly))
"A really good short summary of UML 2.0" - Mike James, VSJ, September 2005  "...is a very complete and precise reference to the latest UML standard. The book is a refreshingly lightweight, weighing in at just over 200 pages. That's not to say it's simply a yellow-pages style reference, because it does contain a wealth of information and explanations of everything it discusses.  If you're a modeller or designer already using UML, I strongly recommend that you take a look at this book. Skimming it from cover to cover will give you a good overview of the new standard, and it will provide an invaluable desktop reference." - Mark Jones, news@UK, March 2006