This book is about modelling the structures and processes that occur within businesses and other organisations. It describes established 'patterns' and illustrates them in UML, the OMG's standard way of diagramming object-oriented systems. This is supposed to help with presenting a business to developers, but the authors had to define their own extensions to UML to get it to work.
The book is not a UML tutorial, although it does contain a brief overview. Some of the diagrams are slightly cluttered and the text itself could benefit from being proof-read by an English teacher; as well as occasional eye-catching errors, there are some sentences that have to be read several times. The style in general seems to be targeted more at business analysts than developers and if (like me) you are quickly tired by text that goes on and on about doing business then this is not a book for you.
The letters UML are too prominent on the cover; the key word is 'business'. Avoid this book unless you are a dedicated business person.