LISP has survived for 21 years because it is an approximate local optimum in the space of programming languages. However, it has accumulated some barnacles that should be scraped off, and some long-standing opportunities for improvement have been neglected. It would benefit from some co-operative maintenance especially in creating and maintaining program libraries. Computer checked proofs of program correctness are now possible for pure LISP and some extensions, but more theory and some smoothing of the language itself are required before we can take full advantage of LISP's mathematical basis.

1999 note: This article was included in the 1980 Lisp conference held at Stanford. Since it almost entirely corresponds to my present opinions, I should have asked to have it reprinted in the 1998 Lisp users conference proceedings.

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