There is provided a device (1) and a method for forming book blocks (21) with two by two glued internal pages comprising a transfer drum (2) formed by two wheels (3, 4) with a plurality of curvilinear pockets (7), respectively spaced by a tooth (8) and respectively adapted to receive a sheet (11), partly pre-folded, with forward folding (19) of a current of sheets (11) reaching substantially horizontally and tangentially in a plane (H) passing through the port ( 10) of the pockets (7) in the upper part of the wheels (3, 4), as well as an opposite extraction table (12) and associated front- wise to the wheels (3, 4) and penetrating therebetween with an abutment projection (13) for the extraction of the sheets (11) from the pockets (7), the sheets being pushed forward in succession on said table (12) in a substantially vertical position one against the other by the sheet (11) and tooth (8) respectively following in the direction of rotation; (F1) of the drum (2).