These are photocopies of the collection; as far as I can learn, there is no print edition available (in 2012). This directory contains transcriptions in ABC music notation, to make the music accessible to software as well as to people who read ABC.
I've followed the common approach of other ABC transcriptions of historic collections: The music has for the most part been transcribed as-is, "warts and all". Some obvious typos have been corrected (and others may have been introduced). Notation that can't be easily represented in ABC has mostly been ignored, though ABC has become good enough that not much need be omitted.
The two major omissions are: The (rare) fingerings aren't transcribed, and the staff breaks aren't preserved. I've followed the usual custom of putting most of the music in 2- or 4- or 8-bar lines, to limit line lengths to about 70 characters. This is to prevent the common sorts of damage done by email software that introduces newlines into longer lines. Backslashes have been used to combine these short lines into 4- or 8-bar staff lines, to get reasonably normal music on D4 and US letter pages. Some of the tunes have irregular phrasing, so this doesn't give good page alignment; in such cases, I've mostly just made it all fit on the page.
An advantage of ABC is that it is very easy to reformat the music for different paper and screen sizes. This is especially useful for people with visual problems. Note that the files here are arranged for a fairly small print size. This is useful for archive and reference copies, but may not be good for some readers. You should reformat the staffs for a size and layout that works best for you. Such things aren't musical information, and don't matter in ABC transcriptions, but can be important when you need printouts that are easy to read.
The primary files here each contain a single tune. The file names are of the form PPPN_TITLE.abc, where PPP is the page number (10-288), and N is the tune's number within the page (1-4). N may also be 0, for the section headers and the headers of tune sets. This produces the same tune order as in the printed books. For multi-page tunes, I've included "dummy" files names PPP1_.abc, to indicate that these pages are included in the previous page's file. You may delete all such files if you prefer. There are merely an accounting gimmick to make it clear which pages were transcribed, but contribute nothing to the collection.