About the Book: The 12th edition of Microeconomic Theory: Basic Principles and Extensions by Walter Nicholson and Christopher Snyder offers a rigorous, calculus-based approach to advanced microeconomics, tailored for upper-level undergraduates and beginning graduate students. This edition enhances clarity and application by integrating theoretical tools with real-world scenarios, emphasizing behavioral economics, and incorporating the latest developments in the field. A standout feature is the two-tier end-of-chapter problem sets: the first tier presents straightforward numerical exercises, while the second delves into more analytical, theoretical, and complex problems, fostering deeper student intuition and understanding