Jeff Gothelf and Josh Seiden's "Who Does What by How Much?" is a practical guide to using Objectives and Key Results (OKRs) with a focus on customer-centricity. The book emphasizes a "value equation" centered on customer behavior and its measurement. It presents OKRs as a process, not just a framework, for aligning teams and achieving strategic goals. This approach stresses outcomes over outputs and promotes agility through regular check-ins and learning. The authors provide a step-by-step methodology for creating and implementing OKRs, including exercises, case studies, and advice on overcoming common challenges. By focusing on customer value and continuous improvement, the book aims to help organizations drive better business results.