Short answers, pulled from the story.
Letters and Papers of the Reign of Henry VIII is a multi-volume edition of calendared documents from the reign of Henry VIII of England. Published between 1862 and 1932, it draws on materials from the Public Record Office, the British Museum, and other archives, arranging them in date order across 21 nominal volumes plus two Addenda volumes, totaling 37 physical books.
The series was edited by three scholars: J. S. Brewer handled the first four volumes covering 1509-1530, James Gairdner edited volumes 5-13 covering 1531-1538, and Gairdner and R. H. Brodie jointly edited volumes 14-21 covering 1539-1547.
A calendared text is slightly summarised and edited, with the language modernised and some explanatory footnotes added, while all substantive content is retained. This differs from a full transcription, which would preserve the original phrasing and orthography.
In nominal terms the series runs to 21 volumes plus two volumes of Addenda. In physical terms, because Volume 1 is represented by a second, greatly expanded edition published in 1920, the complete set amounts to 37 volumes.
The first volume appeared in 1862. Publication continued until 1932, when the second volume of Addenda completed the series. A full reprint was issued by the Kraus Reprint Co. in 1965.
The full text is freely available online as part of British History Online. The series is cited in scholarship as L&P.