Essential LISP by John Anderson et al., published in 1987, was an introductory Lisp book based on research on how beginners learn Lisp.

openlibrary.org/books/OL211803

For code examples it used a subset of features available in most dialects of the time. Where the book differs it goes with Common Lisp with adaptation notes for other dialects, including Interlisp.

@amoroso wrote:
> Where [John Anderson's] book differs it goes with Common Lisp with adaptation notes for other dialects, including Interlisp.

Aside: all the compatibility notes in Guy Steele's book (_Common Lisp: the Language_) were of great value to me.
I wasn't porting programs, but these notes told me a lot about the evolution of the language and the mental processes of the people who worked on that.

#CommonLisp