A glue spreader for spreading glue to a back or adjacent area of a book block of gathered printed pages conveyed past the glue spreader on a conveyor includes a tub for holding the glue. At least one application roller, drivable in the same direction and at the same speed as the book block, is submerged in the tub in order to take up the glue and transfer the glue to the back of the book block. A blade coater is adapted for arrangement above the glue level in the tub at a changeable distance to the application roller. An actuation element is coupled to the blade coater for adjustment of the blade coater for determining a thickness of a glue film to be transferred to the book block back based on the changeable distance to the application roller. A controllable electric motor has a drive element and the actuation element of the blade coater is operatively connected to the drive element of the controllable electric motor.