This is a set of three books by Ryo Asai: "Toki o Kakeru Yutori," "Kaze to Tomo ni Yutori Nu," and "Soshite Dare mo Yutora Nakunatta." They were so interesting that I read them all at once. I recently learned they're trending on social media, so I read a new copy. These books have been handled by someone else, so please refrain from purchasing if you are concerned about the condition.