Marco Cantu's (the author of this blog) books on Delphi are/were a great resource for learning the language.

Btw, his website is under heavy load right now (probably the HN hug?), and this is the error I got:

Error in page: /blog/2019-february-24-years-delphi.html

Error Class: EListError

Error Message: List index out of bounds (-1)

Suggesting that the webserver is written in Delphi... that's dedication :)