Relentless: From Good to Great to Unstoppable is a high-performance mindset book by Tim S. Grover, the renowned trainer of elite athletes including Michael Jordan and Kobe Bryant. Grover explains the mentality, discipline, focus, and competitive drive required to move beyond being merely good or great and become truly relentless.

The book introduces three personality types—Coolers, Closers, and Cleaners—and focuses particularly on the “Cleaner” mindset: someone who thrives under pressure, takes responsibility, refuses to make excuses, and relentlessly pursues results. It applies these principles not only to sport but also to business, leadership, career, and personal achievement.