Paul McJones' History of Lisp has been blogged before (here, here, here, and here), but it keeps getting new content. It's gotten PDFs of 3 early Lisp books from the 1960's, chronologically:
Lisp 1.5 Programmer's Manual (1962) (the year I was born)
The Programming Language LISP: Its Operation and Applications (1964)
LISP 1.5 Primer (1967)
I had read all of them in 1980 when I entered college and went scouring through the university's library for any books on Lisp. I've got the first two, as Amazon still sells the Programmer's Manual new and the second book you can get used.
Modern day Lispers should definitely take a look at these and see how much the language has changed.
Especially take a look at "Lisp 1.5 Primer". This was what I actually learned Lisp from. The horror. It starts off with a couple dozen pages on dotted notation, there's no quote reader macro, you don't start defining functions until page 66 or so, and factorial doesn't get defined until page 96. It took a lot of effort to wade through all of that. I remember trying to code up some of the examples in some weird Lisp 1.5 variant that was on the PDP-11/70 at the time, which was different enough from "real" Lisp 1.5 to make the process exceptionally painful.
But look at that second book and be amazed at how much people got done with Lisp 1.5 in the early 1960's, and remember that they didn't have Emacs at the time, they punched this all in on paper cards and submitted them to the mainframe. Imagine trying to get the number of closing parenthesis right for an expression many cards back. Some of the programs are advanced even for today, although we would implement them far differently today. Those pioneers in the 1960's didn't shy away from the hard problems because they didn't have a fancy IDE with syntax coloring or auto-completion. Note that you may have heard of some of the contributers: Daniel G. Bobrow and L. Peter Deutsch (who was only a teenager when he wrote the implementation for the PDP-1).