No specific yarn brand or type is suggested in the pattern.
Yarn: Worsted weight 1 x 2 oz (50g) ball each of MC, CC1 and CC2.
Measurements: 20.5 in (52cm) would fit an average sized woman’s head.

This hat pattern along with the matching scarf is known by different names in different editions of the book:
Stocking Hat and Scarf
Ice Cream Beanie and Scarf