Java is a complex language with many big, big books on the market. Java Precisely is refreshing in how it combines brevity (just over 100 pages) and depth of information. The other Java book I have is Dietel & Dietel's with though good, can be hard to read due to its size. Java Precisely reads almost as a specification of the language and allows the reader to understand the important principles of the language. Simple but very important concepts like the scope of variables, parameters and fields within a Class are concisely presented. Sestoft has obviously wanted to get away from the 'learn Java by looking at examples' school of thought, such as Dietel anfd Dietel, and is more interested in teaching Java by allowing the reader to understand its important concepts. The concise language he uses has the benefit of brevity, but most pages have to be read a few times to fully understand the concepts he is presenting. The benefit of this is that the reader knows whether or not that he/she has properly understood the text.
Even though thin, the book is a bit larger than a mousepad allowing sufficient information to be presented on each page, with concepts being illstrated by relevant, short pieces of code - 10 to 20 lines.
At just over ten pounds it is a very good investment for those new to Java, with its brief chapters providing a thorough grounding in the language's important concepts.