ompiled over the ten-plus years since the preceding edition, the Seventh Edition comprises new publishers since 2000, publishers we did not include in the Sixth Edition for lack of reliable information, and changes to existing publishers in the years 2000-2011. The content revision is in excess of 2000 items of information: previously-unlisted publishers from 1850 to 2011, or changes in already-listed publishers from the Sixth Edition. The Sixth Edition listed 3642 publishers, as a point of comparison. The Seventh lists in excess of 4600. For practicality and field utility, we have used a lighter, stronger paper to keep the bulk of the book approximately the same as the Sixth Edition. With the demise of Zempel & Verkler's Guide, last updated in 2001 and now out of print, our Seventh Edition becomes the only available guide to this scholarship and the most up-to-date.