Although a British institution, the OED has a policy of attempting to record all the known uses and variants of a word in the varieties of world English, even obscure and outdated one, hence also lists American variants of spelling or meanings e.g., recognize/recognise.
It was originally published between February 1, 1884 and 1928, in over 100 installments or "fascicles", under the title A New English Dictionary on Historical Principles (NED). After the last fascicles were released, the completed NED was published in ten large volumes in 1928. In 1933, the NED was republished in 12 volumes (the very large volumes 9 and 10 of the original NED were each split into two smaller volumes but otherwise unchanged) under the new title Oxford English Dictionary. An additional (13th) volume was added at that time, containing definitions that had been written since the original fascicles were publshed. Between 1933 and the preparation of the Second Edition, an additional three supplemental volumes were added (need to look up the publication dates), so the most complete First Edition-based sets have 16 volumes in all.
The first edition was reprinted in the 1980s in two volumes, with greatly reduced type size. It was called the "compact edition" and was distributed through book clubs. It was packaged with a slipcover that held both volumes and a large magnifying glass to facilitate reading the small type.
The Second Edition (OED2) was published in print in 1989 and on CD-ROM, for the first time, in 1992. Pronunciation of headwords are illustrated by International Phonetic Alphabet instead of a personal symbolism of Editor James Murray.
There have been three versions of the second edition CD-ROM released, each of which has updates and software changes over the previous versions. Version 1 had the same corpus as the printed Second Edition, and the CD itself was not copy-protected. Version 2 had some additions to the corpus, and updated software with improved searching features, but had extensive copy-protection that made it inconvenient to use. Version 3 has yet more words and software improvements, and its copy-protection is, though not completely removed, considerably less annoying than version 2's.
Since March 2000, the Second Edition is also available online by subscription, though it is too costly for individual casual use. Common subscribers are large organizations, such as universities, some of which do not use the OED Online portal and have legally downloaded the entire database into the university library computers. Some public libraries and companies have subscribed as well.
There were a number of editors over the 70 year course of preparing the First Edition. James Murray, who was editor from 1879, got the project off the ground after a slow start, but the scale of the project grew so much, as volunteer readers submitted new words and examples, that he did not live to see the project finished. Another major editor was C. T. Onions. One of its most prolific early contributors, Dr. W. C. Minor, was at the time imprisoned in a criminal lunatic asylum.
A Third Edition, intended as a nearly complete overhaul, is now in preparation.