The method was invented for the construction of the Mirror dinghy. The Mirror is so named because the design was sponsored by the Daily Mirror newspaper, a fact reflected by the historically red sails. The Daily Mirror apparently wanted to bring cheap sailing to the masses. As such, unlike other construction techniques of the day, which required specialist skills and tools, Stitch and Glue was supposed to put boat-building within the reach of the average public.
The technique basically consists of literally stitching together plywood panels with some sort of wire. Once together, the join between the two pieces is glued and commonly taped over (on the inside of the hull). Then, when the glue is dry, the wire can be removed to leave a smooth outer join.