These are some notes from reading Ian Lance Taylor's 20-part essay on linkers. Prettified version on gist.io.
I'm not going to describe the basics of what a linker does because I know already. I talk a little about linkers in How to call Rust from assembly, and I found this Beginner's guide to linkers pretty helpful. Parts [1] and [2] of the essay also discuss "what's a linker?".