This is an advanced text for the course in analysis taught primarily to math, science, computer science, and electrical engineering students. The traditionally separate subjects of 'real analysis' and 'complex analysis' are united in one volume. Some of the basic ideas from functional analysis are also included. This is the only book to take this unique approach. The third edition includes a new chapter on differentiation. Proofs of theorems presented in the book are concise and complete. Each chapter builds upon the other, giving students a gradual understanding of the subject. The chapter-end exercises offer interesting and challenging questions.