Lecture Notes on Functional Analysis

This comprehensive textbook provides a rigorous yet accessible introduction to functional analysis, guiding readers from elementary measure theory through advanced spectral theory. The book is systematically structured across eleven chapters, beginning with Lebesgue measure and progressing through abstract measures, measurable functions, and integration theory before advancing to Banach spaces, Hilbert spaces, and linear operators. Each chapter builds logically upon previous concepts, culminating in spectral theory and applications to Sturm-Liouville equations. Key Features: Progressive pedagogical approach with clear explanations that bridge abstract mathematical concepts and concrete applications through numerous worked examples Comprehensive exercise program featuring problems at the end of each section with complete solutions provided at the end of every chapter for self-study and verification • Complete coverage spanning from foundational measure theory to advanced functional analysis topics, including Lp spaces, compact operators, and spectral theory in a single, cohesive volume This self-contained textbook serves as both a structured course text and a pedagogically oriented reference for independent study. The book is ideally suited for undergraduate and graduate students in mathematics, physics, and engineering, as well as instructors seeking a clear, systematic approach to teaching functional analysis.