The memento box includes a box-like structure having a floor, opposing sidewalls, and a lid hinged to one of the sidewalls. The lid covers the top of the box and defines a closed interior space within the box. A latch or releasable means is provided to keep the lid in a closed position on the box. A plurality of removable and changeable interfitting partitions form a matrix that is sized to fit within the interior space. The height of the partitions and, hence, the matrix is such that when the partitions are placed in the interior space, a book can be stored in the memento box and the interspace within the box above the partitions is at least one-half inch thick to accommodate the book. In addition, the memento box includes a pocket for retaining flat sheet mementos such as photographs. Preferably, the pocket includes a transparent cover. The pocket is attached to the inboard side of the lid. Additionally, the memento box may include a flat divider plate that is removably but securely disposed on top of the interfitting partitions thereby closing the compartments formed by the partitions. The size of the compartments formed by the interfitting partitions can be changed due to complementary slots in the partitions themselves. The person using the box changes the size of the compartments by removing one partition and interlinking different complementary slots on another partition.