The first edition appeared in 1969. The most recent edition, the fourth, appeared in 2000.
The AHD dictionary was a ground-breaking work when it first appeared because it was the first dictionary to be compiled using corpus linguistics for word frequency and other information. The AHD made the innovative step of combining prescriptive elements (how language should be used) descriptive information (how it actually is used), and latter was derived from text corpora. Citations were based on a million word, three-line citation database prepared by Brown University linguist Henry Kucera.
The AHD was also highly praised for its Indo-European etymologies (these were removed in the second but reappeared in the 1992 third edition). The third edition was also a new departure for the publisher because it was developed in a database, which facilitated the use of the linguistic data for other applications, such as electronic dictionaries.
The AHD is larger than the desk dictionaries of the time but smaller than Webster's Third or The Random-House Dictionary of the English Language.
There is a lower price college edition with monocolor printing.