Saddle stitching is the simplest form of binding: two staples are inserted into the spine, holding all of the pages together.
First the cover and book block are collated, with signatures placed one inside the other. Most saddle-stitched projects contain 3 or fewer signatures so that there aren’t more pages than the staples can handle.
Next, the collated pages are put through a stitching machine for stapling. The pages are draped across either side of a “saddle” belt that runs along the entire machine, and the V-shaped belt helps align all the pages at the central fold. The project then moves down the line and staples are inserted at the crease.
Finally, the stapled project is trimmed down to its final size in a guillotine.