This book by Erle Loran was first published in 1943, but it is still a remarkable and fascinating analysis of how Cezanne's paintings work. I have learned more from this book about modern art than from any other single work.
Loran was himself a painter, who went to Provence and stayed in Cezanne's old studio. He found the sites of many of Cezanne's paintings and photographed them with a cheap camera. Years later, he analysed each picture, placing it by the photograph of the motif, thus showing exactly how Cezanne changed things around. Cezanne is often noted for his colour and his brushwork but this study makes clear how fundamental composition was to his painting. Comparisons of the same landscape painted by Renoir and by Cezanne, and again by Pissarro and Cezanne, are particularly revealing.
If I were seeking to learn to paint, I would use this book as my text! It is rather dogmatic in places but Loran's method of using diagrams and arrows to illustrate the dynamics of a picture is wonderful.