Sites like Azbyka.ru and Pravoslavie.ru often host free, legal PDF versions of classic theological and technical texts on iconography.
A highly visual guide that breaks down the layered process of tempera painting. History & Art Theory ikonopis kniga skachat
If you want to "read" an icon—understanding its symbols and theological meaning—these are the best starting points: Sites like Azbyka
A comprehensive overview based on the British Museum's collection, covering the development of iconography across different nations and eras . ikonopis kniga skachat