Physically Based Rendering: From Theory to Implementation

off topic: I live in this strange world where I can read the code and understand what it does, regardless of the language(!)

but the algorithm for the theory looks approximately like this to me

    (ijfio) $@ * foiew(qwdrg) awep2-2lahl [1]

Is there a good book that goes FROM programmer TO math-wizardry that you would recommend, without falling into the textbooks? Ideally I'd like to be able to read them and turn them into pseudocode, or I can't follow.

[1]: e.g. https://pbr-book.org/4ed/Introduction/Photorealistic_Renderi...