Mr. Steggle suggests that Mrs. Shakespeare’s movements should be reconsidered with an eye to her “possible absences from London rather than her perpetual absence.”

The note to Mrs. Shakespeare concerned money for a fatherless child named John, who was an apprentice, though not under the famous playwright, with the last name “Butte” or “Butts.” It called upon her to pay money that was most likely held in trust for him, a pledge that her husband may have undertaken, and it referred to a time when she “dwelt in trinitie lane,” which Mr. Steggle now believes refers to a location in London.

The book that held the letter was a 1608 text printed by Richard Field, a native of Stratford who was Shakespeare’s associate, neighbor and first printer, according to Mr. Steggle. Wastepaper was commonly used in bookbinding, and “given Field’s extensive known links to the Shakespeares,” the discovery of their family documents in a work he published indicates it was likely addressed to the famous Mrs. Shakespeare, Mr. Steggle said. Notably, the response, which appears to come from her, sounds “organized, businesslike and rather sarcastic,” he added.

As for John Butts, the child in the letter, his name did appear in a 1607 record of an institution that disciplined disobedient apprentices, among other records, and Mr. Steggle said his surname did arise in “Shakespeare’s extended personal network.”

“The stakes are high,” Mr. Steggle writes in his paper. “This letter, if it belongs to them, offers a glimpse of the Shakespeares together in London, both involved in social networks and business matters, and, on the occasion of this request, presenting a united front against importunate requests to help poor orphans.”