Why is this important? We do not have his plays in his hand. The quartos are the closest thing we have, some of them have what is believed to be his hand-written notes in the margins. Eighteen of Shakespeare’s plays had appeared in quarto editions by the time of his death in 1616. Another three plays were printed in quarto before 1642. In 1623 an expensive folio volume of 36 plays by Shakespeare was printed, which included most of those printed in quarto.
Lo these many years, only those scholars that could afford to travel to and spend time in the Bodleian Library in Oxford and Folger Shakespeare Library in Washington DC could pore over the quartos in detail.
In the 1603 quarto of Hamlet, we find:
Hamlet: To be, or not to be, I there’s the point, To Die, to sleep, is that all? I all…
In the 1605 quarto we find:
Hamlet: To be, or not to be, that is the question, Whether tis nobler in the mind to suffer…
The "first quarto" (Q1) also has a Queen/Horatio scene after Ophelia’s mad scene that suggests a conspiracy between Hamlet’s supporters to counter the King/Laertes conspiracy scene.
Hopefully all the participating libraries will offer this free, but you will be able to purchase and DL facsimile copies from Octavo.