The present book is a teaching text designed to introduce the fundamentals of the subject of statistical mechanics at a level suitable for students who meet the subject for the first time. The treatment given is designed to give the student a feeling for the topic of statistical mechanics without being held back by the need to understand complex mathematics. The text is concise and concentrates on the understanding of fundamental aspects. Numerous questions with worked solutions are given throughout.
This book is fairly good, though rather confusingly marketed as an introductory work; it is an introduction for undergraduate students who have already studied thermodynamics and quantum mechanics (at an introductory level) as well as mathematics relevant to the study of physics. Once you accept that this is the necessary background for understanding the book, then you're doing alright.
The writing is fairly engaging, though densely technical (even where it tries to chop that up with some humor) which is understandable given that it is a fairly short manuscript that is meant to accompany lectures. As a stand-alone, it seems adequate for some basic conceptual work, and like a good stab at trying to fit statistical mechanics into the broader picture in physics (with the hope that the reader will connect it to a literature they are already comfortable with). There are some areas where the content could use a little fleshing out or clarification, though in those areas, the authors are usually comfortable with acknowledging their over-simplification.
By and large, this is an interesting book, but likely not the best available introduction and certainly not the most accessible for newcomers to the field; it does require someone knowledgable to bounce some of the content off of, in order to make sure that you are getting the most out of it. If you are starting an independent study, I recommend looking somewhere else, but as an accompanied exploration, this puts you in rather good shape.