Who invented the screwdriver?

There is no single inventor noted for the screwdriver. It was invented in Germany in the late fifteenth century. Strangely enough the screwdriver is obscure and not mentioned in texts even though screws were evident in many applications during this early period.

The following information comes from Witold Rybczynski's book: One Good Turn: A Natural History of the Screwdriver and the Screw. ISBN: 0-684-86729-X

The earliest published evidence found by Rybczynski of screws as we know them, threaded, with heads shaped for driving by a tool, and used to fix two work pieces together, is in a manuscript known as The Mediaeval Housebook, thought to be written in southern Germany between 1475 and 1490. This manuscript shows leg irons and manacles fastened with slotted screws.