For anyone interested in reading on density, neighborhoods, and what sorts of things work well in cities, I can't recommend The Death and Life of Great American Cities by Jane Jacobs enough[0]. She wrote the book in the 60s and it has really stood the test of time.

Edit: I'd add that the book does a good job about explaining the sorts of motivations there were behind un-densifying cities (or keeping density from rising) in the first place.

[0]: https://en.wikipedia.org/wiki/The_Death_and_Life_of_Great_Am...