Long before my university degree in fine art/visual arts the Ilford Manual of Photography was the standard reference tome for people keen on learning photography in a scientific way before embarking on serious study. I still have my much annotated, rabbit-eared orange-covered book published in 1974 and the principles discussed are timeless. I concur with other posts here that today, much of the content is quite dated. In fairness, there are many hundreds of excellent references besides Ilford's, just that it was then very much a definitive technical and explanatory reference in the 60s and 70s. One of the more modern gems is Canon's Lenswork books (I to III): read up on the Five Aberrations of Seidel which leads to understanding lens MTF curves and thus potential and real performance.