The Lambda Papers are a series of seminal works on programming language design and implementation written by Guy Steele and Gerry Sussman.
You may have heard about them because of the very popular Lambda the Ultimate website, or maybe you just heard about them because you are studying Scheme, or are a student of programming history. Whatever the case, they are very much worth reading (you’ll have to trust me on that).
You should start with ‘AIM-353 Lambda:The Ultimate Imperative’ and follow it with ‘AIM-443 Lambda: The Ultimate GOTO’. Both may be found here.