I learned more reading through this guide than I did going to college. So good!
This keeps coming round but I'm so glad it does—it's one of the few resource that could be posted on DN every day and I wouldn't mind, so thorough.
Probably my favorite resource for learning typography. I wrote a post about 5 ways I improved my typography skills and this was one of them:
Helvetica is one of my favorite films. I want to share it with all my friends, but they never understand.
Butterick made #7 on my recent list: