This document discusses the principles of lean startup applied to building new products for new markets. It summarizes 5 key principles: 1) Eliminate waste, 2) Start small, 3) Deeply understand customers, 4) Take a scientific approach, and 5) Focus and get things done. For each principle, it provides explanation and examples to illustrate how to apply the lean startup methodology through minimizing risks, learning quickly, and iterating products rapidly based on customer feedback.