From the Book:
Knit in stockinette stitch, with a rib trim and a shaped crown, this hat is worked with just one ball of bulky-weight yarn. A very quick knit, it can literally be made in a single evening. The hat is shown here in both basic black and a classic stone shade, but you could make it in a variety of seasonal colors.
The book lists 10 (6.5mm) and 10.5 (7.0mm) as required needle sizes.