Abstract: A device for manufacturing thread-stitched book blocks which comprise folded printed sheets has a conveying apparatus which transports the printed sheets astride a stitching saddle into a stitching position and to which the printed sheets are fed. A stitching apparatus is arranged at a lateral spacing from the stitching saddle which can be driven in an oscillating manner and can be supplied with printed sheets by the stitching saddle. The conveying apparatus is controlled in order to change the conveying speed and/or the stitching position of the printed sheets on the stitching saddle, in that the conveying apparatus is drive-connected to a controlled-rotation electric motor which is controlled by a computer-connected controller.