This short review was originally conceived as one of a series of lectures on the history of the theory of ore formation, to be delivered at the Institute of Applied Geology. It outlines, though by no means exhaustively, an interesting modern view of petrogenesis and ore formation.

The concepts of classical geology are criticized by the advocates of the persedimentary theory. According to them, all igneous rocks are sediments transformed without addition of juvenile matter. They consider the relatively high alkali content of many marine sediments instrumental to this "plutonization" of sediments.

Persedimentarists believe that cyclicity of geologic history is a major cause of rock differentiation and the formation of ore deposits.