Dynamic Asset Pricing Theory is a textbook that explains how to price assets and build investment portfolios over time in uncertain situations. The key ideas are state prices and martingales, with a focus on simplicity using Brownian motion. The book covers topics like bond pricing, options valuation, and portfolio optimization using numerical methods like Monte Carlo simulation. The second edition is longer and includes new chapters on bond pricing and derivatives. Overall, this textbook is a comprehensive guide for understanding and applying asset pricing theory in real-world scenarios.