Abstract: In an index selector device of the kind for use with a stack of index cards housed between a base and a lid hinged together and having a selector on the lid to release the lid after moving card-engaging members into engagement with a card so as to raise all the cards in the stack above the one required, the selector is a plurality of push buttons, one to each card-engaging member, arranged in two rows at right angles to the hinge. Interengaging inclined surfaces on each push button and card-engaging member cause lateral sliding movement of the card-engaging member on depression of the push button. A hook on the card-engaging member moves under the edge of the card above the one required and co-operating inclined surfaces on the inner end of the card-engaging device and a central catch bar cause the catch bar to release the lid. A barb on the card-engaging member hooks into a recess on the catch bar to hold the card-engaging member in the card-engaging position while the lid is open.