To enable one surface of a book cover to be easily slipped between any opened/closed pages by using a book cover attached to a book and making several fold lines in a fold part of the book, and to mount a column, where a subscription day and a memorandum can be described, on the inner surface of the book cover.

A proper number of the fold lines 3 are made in the part of the book cover 2 to be tucked in the front surface of the book 1, and the book cover 2 can be easily inserted in the opening/closing part of the book 1. There is mounted on the inner surface of the book cover 2 the column 4 where the subscription day or memorandum can be described without using many sheets of paper.