Shakespeare's 'co-author'
As an example, the word "ruttish" appears in the play, meaning lustful - and its only other usage at that time is in a work by Middleton. The distinctive way that stage directions are used in places is much closer to Middleton's style than to Shakespeare, says the study. There cannot be any definite conclusion to this kind of literary detective work - and the academics say there could be other candidates such as John Fletcher - but Prof Maguire says there is an "arresting" stylistic match with Middleton.
Changelings
Thomas Middleton, who lived between 1580 and 1627, was a Londoner, younger than Shakespeare, and Prof Maguire says his more modern grammar can be detected in the text. Middleton became a celebrated writer - remembered for works such as The Changeling and Women Beware Women. But Dr Smith says that his collaboration with Shakespeare in about 1607 could be likened to an established musician working with a rising star. The question of the authorship of Shakespeare's plays has been a continued source of speculation and conspiracy.
Prof Maguire says that there is no serious scholarship which challenges the idea that Shakespeare wrote the plays attributed to him. But she says the latest research suggests a much more collaborative approach to writing plays for the Elizabethan and Jacobean stage. Plays were written quickly and for a commercial audience - and there were often stables of writers who worked together to produce a play.
Writers within these teams had specialised roles, she says, such as people who were particularly good at writing plots. Prof Maguire says the cultural reverence for Shakespeare - so-called "bardolatry" - has helped to support the idea of the playwright as a creative genius, producing his works in isolation. While much of Shakespeare's writing is his work alone, she says that in All's Well That Ends Well there is another writer - so much so that in places one author seems to be handing over to the other.
The play itself recognises the mixing and matching of life. "The web of our life is of a mingled yarn, good and ill together." Or else, as it says later: "It is like a barber's chair that fits all buttocks."
By Sean Coughlan