[multiplegeorges]

The guides are great for someone doing what most people use Rails for. Recipes with some side cases are very appropriate for that audience.

If you want to know more about an API, there's https://api.rubyonrails.org and the classes are quite will documented. These docs don't show up in the guides and might be what you're looking for. I should also point out that the API docs are directly linked in the header of the Guides.

Specifically for routing, there's lots of additional detail here: https://api.rubyonrails.org/classes/ActionDispatch/Routing/M...