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"Endpapers" or "flyleaves" refer to the blank sheets that the bookbinder must sew (instead of gluing) to the front and back of a book after it has been sewn.
Binding endpapers are sheets of colored, spattered, marbled, satin, or even gilded paper, one part of which is glued to the inside cover boards and the other part to the face of one of the blank endpapers.
