From a Shakespeare Authorship FAQ:
Additionally, the diarist Phillip Henslowe recorded a performance of a King Leare in Easter of 1594. Would it not be the most straightforward conclusion that in fact an early version of Shakespeare's Lear was already kicking around during the 1590s?
No it would not. Even though I'm a mere intelligent (or "intelligent") outsider, I know that the "straightforward conclusion" is absolute bunk. It's well known that there was an (anonymous, but attributed variously to Kyd and others) old version of King Lear knocking around before Shakespare got to his: it's even online.
As an occidental interdisciplinary enthusiast, it's pretty difficult to avoid The Bard, but I'm glad that I can study the field without having to produce any scholarly work on the subject: the precedent for Shakespearian study is quite overwhelming, with barely a stone unturned and conjecture running rampant, as above. If books on Shaksperian Punctuation are the limit, books on Marxism in Shakespeare are almost certainly over it.
Anyway, today's quote-that-really-ought-to-be-online is from H.H. Furness:
When [...] between every glance we try to comprehend each syllable that is uttered, or strain our ears to catch every measure of the heavenly harmony, or trace the subtle workings of consummate art,—that is a far different matter; therein lies many a lesson for our feeble powers; then we share with Shakespeare the joy of his meaning. But the dates of the plays are purely biographical, and have for me as much relevancy to the plays themselves as has a chemical analysis of the paper of the Folio or of the ink of the Quartos.
From his preface to A Midsummer Night's Dream, variorum edition, 1895.