A method and an apparatus for the thread-stitching of folded signatures, for which individual folded signatures which are successively lined up along their flat sides are sewn together with at least one sewing needle and at least one hook needle to form a book block. Prior to penetrating the fold of the signature to be sewn from the inside to the outside and before penetrating the eyelet of the previously sewn signature, the hook needle is rotated in such a way around its longitudinal axis that its hook is positioned in a vertical symmetry axis of the eyelet, on a side of the hook needle that faces the previously sewn signature. The hook needle can be rotated for this at an optional angle (α) around its longitudinal axis and the hook can be positioned at an optional rotational position.