PURPOSE: To simplify the work of a clerk in a bookstore at a bookstore front and settle controversial points such as the falling of the conventional paper bookmarker by a reader, the conventional paper bookmarker is an encumbrance to a reader and the like by a method wherein a string bookmarker is provided at the central upper part of a book and library cover.

CONSTITUTION: A string bookmarker 2 is provided at the upper part of the conventional book and library cover. Thus, at the use of the bookmarker, only the application of a cover is enough for a clerk in a bookstore and a user, resulting in allowing to annule the extra labour for putting the paper bookmarker between pages, Further, when a reader is not yet finished and stopped on half way in reading, the putting of the string bookmarker 2 provided on the cover between pages half-read is enough. As a result, neither the falling of the conventional paper bookmarker nor the encumbrance with the paper bookmarker at reading occurs to a reader.