O'Reilly - Learning UML v2.0 (Apr 2006).chm
Since not everyone is new to UML, there are two main routes through this book. If you're new to UML as a subject and want to get an overview of where the modeling language came from, then you should start with Chapter 1. However, if you want to get your hands dirty as quickly as possible, then you can either skip the introduction chapter to delve directly into use cases or jump to the chapter that describes the UML diagram in which you are most interested.
Now you know what Learning UML 2.0 is about, it should be explained what this book is not about. This book is not about any one particular modeling tool or implementation language. However, some tools have their own way of doing things, and some implementation languages do not support everything you can legally model in UML. Wherever appropriate, we have tried to point out where UML tools or implementation languages deviate from or follow the UML standard.
Lastly, because of the large variation in software development processes, this book is not about any particular process or methodology. Instead, it focuses on modeling and provides guidelines about appropriate levels of modeling that can be applied in the context of your software development process. Since this book adheres to the UML 2.0 standard, it works alongside any process or methodology you use.