Of the more than sixty early Shakespeare quartos, only two were issued without title page dates. It has been conjectured (although not definitively) that Q4 Romeo and Juliet and Q4 Hamlet date from 1622 and 1625, respectively. Scholarly interest in whether one or both quartos influenced the text of the First Folio has fueled recent attempts to adduce bibliographical evidence to date the two quartos with more certainty. Hailey shows that a date for Q4 Hamlet of 1619–21, on the basis of deterioration of Smethwick’s publisher’s device, is faulty, while an effort to date Q4 Romeo and Juliet by its paper stocks proves to be inconclusive. Rightly understood, however, the comparative analysis of paper stocks, including but not limited to their watermarks, can be a powerful forensic tool for dating imprints more precisely. Hailey explains how and why paper can be useful for dating, and he describes his method for collecting and analyzing paper data. Primarily on the evidence of their paper stocks, Q4 Romeo and Juliet is dated with a high degree of probability to 1623; Q4 Hamlet is demonstrably dated to 1625. Thus, neither of these quartos could have influenced the First Folio text, and the unique shared readings between Q4 and Folio Hamlet texts must result from the Folio’s influence on Q4.