This book—the first of two companion volumes, together with a third dedicated entirely to exercises—is devoted to introducing the standard techniques of statistical mechanics; presenting a practical, operative, and attentive approach to the recurring structures that link different areas of statistical physics. It strikes a balance between breadth and an accessible walk-through approach to calculations and concepts that students and researchers will encounter across the many corners of modern statistical mechanics. It is a broad, accessible starting point enabling readers to then move on to more focused and advanced treatments. It also touches on topics that have become increasingly relevant in recent years, including applications of machine learning to elements of quantum information and computing. Chapters include short experimental boxes that connect theoretical concepts with laboratory demonstrations—from critical phenomena in fluids and magnets to frustrated spin systems. To support learning by doing, it also provides simple numerical codes that illustrate several topics throughout the text. This will serve as an ideal textbook for undergraduate and graduate courses on Statistical Mechanics and Thermodynamics. It can also be used as supplementary reading for courses on Many-Body Physics. Key Features:A one-stop compendium of major results of standard and modern Statistical Mechanics. Includes pedagogical boxes containing worked examples, historical perspectives, suggested further activities, and experimental notes and connections to real world systems. Each chapter is structured to serve as a two-hour lecture on the topic, with accompanying calculations.