A book explaining how to use smartphones to improve memory, thinking skills, and concentration. - ISBN: 9784413231121 - Price: 1380 yen - Title: Smartphone Study Revolution - Author: Takayoshi Yoshida - Focus: Memory, Thinking Skills, Concentration - Usage: Smart smartphone usage for smart people Thank you for looking. I believe there are no particularly noticeable scratches or stains. Please understand that this is based on a personal assessment, and kindly consider purchasing if you are comfortable with this.