A comprehensive, practical guide to valuing businesses and securities that explains the theoretical foundations and step-by-step application of methods such as discounted cash flow, relative (comparable) valuation, and contingent-claims/option approaches, while addressing how to estimate key inputs (cash flows, growth, risk, discount rates, and terminal values), adjust for capital structure and liquidity, and handle special cases like financial firms, private companies, and distressed or high-growth firms; the book emphasizes real-world implementation through examples, case studies, and spreadsheet-based techniques.