I purchased these books about 15 years ago, and I've opened the first two. Books 3 through 5 are unopened. The opened books have some stains on the pages. Please consider this when making your purchase. You can also purchase just one book. Human Resource Development Course, President Business School c-1: Zen Humanism by Taizo Matsubara c-2: The Knack of the Game by Eio Sakata c-3: Nurturing and Utilizing People by Genji Fujita c-4: There is No Limit to Wisdom by Chiyoji Misawa c-5: Responding to Paradigm Shifts #Economics #HumanResourceDevelopmentCourse #HumanSkills #PresidentBusinessSchool #Business #SetOf5Books #Learning