A security booklet 10 comprises a plurality of leaves 15, 20, 30 attached together by stitching 40; the plurality of leaves 15, 20, 30 comprise an inspection page 16, 54 and an adjacent leaf 20; the stitching 40 is exposed at the inspection page 16, 54 and the adjacent leaf 20 comprises at least one window 23 in which at least part of the exposed stitching is visible when the adjacent leaf 20 is arranged to overlie the inspection page 16, 54. The security booklet may be a passport, passbook, identification booklet or the like. A security booklet comprising a book block formed of a plurality of folded sheets that are stitched along a line offset to the fold line is also disclosed.