It’s helpful to realize that Alexander went through three distinct periods in his life:
1.
Notes on the Synthesis of Form and
A City is Not a Tree we’re starting out extremely mathematically, although he quickly picked up that something didn’t quite work.
2.
A Timeless Way of Building and
A Pattern Language explore the other extreme and look for practical ways to bring about the quality without a name through process and focus on the human side of building.
3. But even the patterns didn’t ultimately help people create what Alexander had in mind and so he tries to synthesize both extremes in his magnum opus
The Nature of Order.
Alexander went through these three distinct periods in which he changed his thinking considerably. Unfortunately, his most well-known books are from the earlier periods. Many ideas in them Alexander himself has deemed obsolete, and he has improved on them in more recent but less familiar works, like
The Nature of Order.
If you want to read a little more about these periods, I recommend this article:
https://patterns.architexturez.net/doc/az-cf-218793
And as this turns into a “best of” I’d also add Ryan Singer’s primer:
https://vimeo.com/491222729