I recommend starting with the Pharo Mooc.  And then deep dive on their books .
From there you can read old classic smalltalk books, such as Kent Back's "Smalltalk Best Practices" and Chamond Liu'a
"Smalltalk, Object and Design".
For what it is worth, a lot of Smalltalk is captured by Ruby. Like the ability to add methods to integers.
It was ok because I wasn’t trying to use it in anger. Just very simple stuff where looking at the source was good enough.
Lots of objects there as well and it's super practical.
Not sure about Smalltalk besides amusing friends during a beer