“5xWhy. Handbook” is the first manual for world-famous problem solving technique popularized by the founder of Toyota Industries CO. Ltd. Sakichi Toyoda. The method of solving problems by using a series of questions "why?" is the basis of all production and services management methods, as Lean Management, Six Sigma, Deming’s Total Quality Management, Toyota Production System, Total Production Maintenance and S & OP. This book is also probably the first position based on research using the Kano model. This model allowed the separation of the basic characteristics which are expected from good handbook by readers. If the authors' experience could be summed up, the book would contain 50 years of practice and theories learned through hundreds of books and academic studies. The book is addressed to anyone who want to continuously improve processes, people or himself. The keynote when writing the manual was to encourage reading not only executives and middle-level employees, but most of all employees directly supporting processes - because without them no improvements are not possible.