It was first published 1968-2003 in 73 volumes under the editorship of Allen Kent, Harold Lancour and Jay E. Daily.
His findings mention “omissions, errors, inaccuracies, and inconsistencies; inadequate cross references; lack of uniformity of style; lack of balance in the length of articles; inadequate references and bibliographies.” He concludes that “although as an encyclopedia, the encyclopedia is a failure, it contains many excellent articles.” James D. Anderson reviewed the 2nd edition.
Overall, it appears to be a spin-off aimed primarily at making money rather than describing the state of the art in the twenty-first century.
[5] He notes: "Of the 565 articles, more than 400 are completely new to this edition, amounting to about 70 percent of total material."
He concludes: "There is simply no other work that comes near it in scale or spread and for librarians and information specialists it must be regarded as the pre-eminent reference source for the profession."