A book that emphasizes the importance of alone time for strengthening the mind. - Title: Alone Time Strengthens the Mind - Author: Satoshi Uenishi - Publisher: Seishun Publishing - ISBN: 978-4-413-21098-0 - Price: 1000 yen + tax I read it once and then stored it with a cover. There are no visible stains, but the top of the cover is slightly yellowed, and there is a slight warp to the book. Please check the photos. Thank you.