Acronym agglomeration is an affliction of the age, and there are acronym addicts who, in their weakness, find it impossible to resist them. More than once in recent months my peers have cautioned me about my apparent readiness to use not only acronyms, but abbreviations, foreign isms, codes, and other cryptic symbols rather than common, ordinary American words. Many among us, though, either have not received or have chosen to ignore such advice. As a consequence, what we write and speak is full of mystery and confusion. It is then for the reader and listener and for the writer and speaker that Reta C. Moser has compiled this guide. Its effective application to the art of communication is urged. Such use should help avoid many of the misunderstandings involving terminology which occur daily. Although such misunderstandings are certainly crucial in humanistic and social situations, they are often of immediate import and the trigger to disaster in scientific, technical, and political situations. Some 15,000 acronyms and 25,000 definitions are provided (a 50- and 47 -percent increase over the 1964 edition!), with due credit to Miss Moser's diligence in making the compilation and with the acknowledgment that the acronymical phenomenon is very much with us. This edition, like the first, is certain to be of value to writers, librarians, editors, and others who must identify and deal with acronyms.