What is "jest book"

Jest \Jest\ (j[e^]st), n. [OE. jeste, geste, deed, action, story, tale, OF. geste, LL. gesta, orig., exploits, neut. pl. from L. gestus, p. p. of gerere to bear, carry, accomplish, perform; perh. orig., to make to come, bring, and perh. akin to E. come. Cf. Gest a deed, Register, n.]

1. A deed; an action; a gest. [Obs.]

   The jests or actions of princes.
   --Sir T. Elyot.

2. A mask; a pageant; an interlude. [Obs.]
   --Nares.

   He promised us, in honor of our guest, To grace our banquet with some pompous jest.
   --Kyd.

3. Something done or said in order to amuse; a joke; a witticism; a jocose or sportive remark or phrase. See Synonyms under Jest, v. i.

   I must be sad . . . smile at no man's jests.
   --Shak.

   The Right Honorable gentleman is indebted to his memory for his jests, and to his imagination for his facts.
   --Sheridan.

4. The object of laughter or sport; a laughingstock.

   Then let me be your jest; I deserve it.
   --Shak.

   In jest, for mere sport or diversion; not in truth and reality; not in earnest.

   And given in earnest what I begged in jest.
   --Shak.

   Jest book, a book containing a collection of jests, jokes, and amusing anecdotes; a Joe Miller.

Jest books (or Jestbooks) are collections of jokes and humorous anecdotes in book form - a literary genre which reached its greatest importance in the early modern period.