This textbook provides a complete survey of the broad field of statistical mechanics. Based on existing lectures, it stresses a special pedagogical approach to this topic. The authors clearly distinguish between general principles and their applications in problem solving. Analogies between phase transitions in fluids and magnets using continuum and spin models are emphasized.; This book has special features like historical notes, summaries, problems, mathematical appendix, computer programs and order of magnitude estimations. Due to its extensive list of references for technical details on advanced topics, this book is for students and also for researchers in the field of condensed matter physics, materials science, polymer science, solid state physics, and astrophysics.