Abstract: A book sewing machine having an incorporated automatic feeder is disclosed. The automatic feeder has two stacks of signatures and acts to remove one signature from each stack simultaneously. The two signatures are both opened and then placed directly astride a sewing saddle of the sewing machine. The sewing saddle carries means for adjusting the spacing of the two signatures, and means for holding the two signatures in place as the sewing saddle moves to the sewing position where the two signatures are both sewn in one operation and then passed for further processing. One embodiment incorporates an automatic paster which applies paste to the signatures adjacent their backbones prior to placing them on the sewing saddle.