From The FreeOnLineDictionaryOfComputing:

A dialect of the LispLanguage developed in 1967 by Bolt, Beranek and Newman (Cambridge, MA) as a descendant of {BBN-Lisp}.  It emphasises user interfaces. It is currently supported by {Xerox PARC} [XeroxParc].
  
Interlisp was once one of two main branches of LISP (the other being {MacLisp}).  In 1981 {CommonLisp} was begun in an effort to combine the best features of both.  Interlisp includes a Lisp programming environment.  It is {Dynamically''''''Scoped} [uses DynamicScoping]. NLAMBDA functions do not evaluate their arguments. Any function could be called with optional arguments.
  
["Interlisp Programming Manual", W. Teitelman, TR, Xerox Rec Ctr 1975].

I recommend ["INTERLISP : the language and its usage", S.H. Kaisler, John Wiley & Sons, 1986], sometimes titled just "INTERLISP".
----
Also see TheEvolutionOfLisp.
----
CategoryLisp CategoryHistory