Introduction This page examines the earliest surviving Lisp compiler, written by Timothy Hart and Michael Levin around 1961. To avoid repetition of phrases like “the compiler”, we will use the abbreviation “HLC” (for “Hart–Levin Compiler”) to refer to it. The HLC was introduced in M.I.T. AIM-039 and documented more fully in the LISP 1.5 Programmer's Manual by McCarthy et al. For information about