Editions
Joachim Meyer was quite prolific when it came to the production of fencing literature in the 16th century. We know that he produced an earlier handwritten and lavishly illustrated manuscript in 1560 which formed the basis for his more widely known 1570 book (with woodblock illustrations) printed originally in Straßburg and again in Augsburg in 1600.
A digital version of the handwritten manuscript from 1560 is presently available for download (as a PDF) thanks to the Lund Universitets Bibliotek:

Meyer's Early Manuscript
There are also two online editions of Joachim Meyer’s printed book presently available for download (as PDFs) thanks to the Münchener DigitalisierungsZentrum Digitale Bibliothek and the Bayerische Staatsbibliothek:

Meyer's 1570 Edition
See Links for more information, including links to modern English editions and translations.