"Hyper-Focus to Control Yourself" Price: ¥1,400 "Hyper-Time Management: The Ultimate Guide to a 40-Hour Workweek" Price: ¥1,400 Author: Both by Mentalist DaiGo These two books are recommended for those who want to improve their study efficiency or become better at managing their time. They are also suitable for those interested in psychology or self-improvement. Both were purchased new and have been read once, so they are in relatively good condition. However, they are used items, so we appreciate your understanding before purchasing.