A Gull's Hornbook (heavily vacuumed to perhaps just 25% of the original) A Gull's Hornbook, or what we might call A Fool's Instructional Manual, is a famous satirical pamphlet by Thomas Dekker that details a day in the life of a London-fool. Shakespeare might have been aware of this pamphlet before he created Sir Andrew Aguecheek, in Twelfth Night.