I use Java to create games so I have quite a bit of knowledge with the language which makes this book quite easy to understand; beginners might struggle a little as some parts are a little complex.
This book teaches what TCP/IP networks are, how they work and then how to program them.
You'll learn to create programs that are capable of various networking functions and with the skills learned here you can move on to greater things. 'It will not make you an expert' but you'll be able to search your network for IP addresses, communicate with servers, send information etc from the programs you create.
This book is nice and clear and I intend to recommend it for my students. What I like about the book is that it is fairly short and does not intend to be comprehensive. What I am not so happy about is all the stuff on about how to encode data (Chapter 3). A beauty of Java is that it has Object Serialization which means we don't have to worry about encoding data as it is done for us. We can transmit these objects between sockets without having to worry about implementation details. Sadly, the book does not explain Object Serialization at all. If this book had a section on Object Serialization instead of the Encoding Information section I would use as the main course text book.