Marty Cagan was ten years into his engineering career when he began questioning the purpose of his work. Frustrated with the products he was building, he wondered why they were necessary—but soon, he realized that asking "why" was the job of the product manager, not the engineer. So, he became one. Not just any product manager, but a leading expert in the field. Now, through Silicon Valley Product Group, Marty helps companies transform the work behind their products to build meaningful result...