For the topic of optimization, I recommend: https://people.csail.mit.edu/jsolomon/share/book/numerical_book.pdf https://people.csail.mit.edu/jsolomon/share/boo

For the topic of optimization, I recommend: https://people.csail.mit.edu/jsolomon/share/book/numerical_book.pdf https://people.csail.mit.edu/jsolomon/share/book/numerical_b... It will give you a decent introduction to optimization methods underpinning deep learning. Deep learning theory is optimization theory. There are youtube lectures as well and Justin is a great lecturer. I personally would not recommend the Goodfellow book. It's not a good book for newcomers, at best it's a quick reminder of how some things work on a non-rigorous level.