First of all, a few words about the structure of the book. Each chapter covers a complete topic and is devided in three parts:
The first consists of the theory of the topic, which is illustrated with a few examples. The second part contains a few exercises, either of theoretical nature or programming tasks. The third part, called 'practice session', instructs how to use a prolog interpreter and helps to discover the features of the interactive environment. The exercises are mainly programming tasks.
Although prolog is a programming language and commonly not the first language someone starts learning, the book doesn't expect one to have knowledge in other languages. It starts at the very beginning and ends with advanced topics like database manipulation and working with files.
All in all it's more focused on how to use prolog than on how the prolog interpreter works, though it contains a few hints and a little piece of theory, which is needed.
It's quite easy to read and doesn't take a long time to work it through.
It actually deserves a fifth star if there were not the high price. Hope you enjoy learning prolog with this book.