The Lean Tool Room. Problem Solving, Understanding You Have a Problem by Mark Roberts is a book that explores in depth the 'Lean' business model. It explores the origins of the 'Lean' system and is a detailed guide for both employers and employees who want to know more about this system or may be considering implementing it in their business. Packed with useful information and diagrams, this book will appeal to anyone with an interest in business or the Lean business model.