A book forming and pressing machine includes a reshaping device to perform a shaping operation on a book block, a pressing device having a number of spaced-apart pressing plates and burn-in rails to press the book block during the shaping operation, and a loading device that includes a loading table. The loading table includes a book block back support arrangement to support the book block back during the shaping operation. The latter arrangement includes at least one pair of prism plates having shaped upper edges and arranged spaced-apart, extending parallel or quasi-parallel to each other to support a correspondingly shaped book block back during the shaping operation. The arrangement further includes at least one feed element operatively connected with each prism plate and adjustable to a position to support a differently shaped book block back in place of the shaped upper edges of the prism plates.