1. Fractionation in igneous processes. - 2. Compositional variation in magmas. - 3. Phase diagrams introduction. - 4. Ternary systems I. - 5. Ternary systems with solid solutions page. - 6. The interpretation of two-element variation diagrams. - 7. Petrographic aspects of volcanic rocks. - 8. Quaternary systems. - 9. Experimental work on natural basaltic and allied rocks. - 10. Water-bearing basic rock systems. - 11. Compositionally zoned magma bodies and their bearing on crystal settling. - 12. Petrographic aspects of plutonic rocks. - 13. The interpretation of data for plutonic rocks. - 14. Trace elements in igneous processes. - 15. The use of isotopes in petrology. - Appendices. - 1. Nomenclature of igneous rocks. - 2. Average major element compositions and CIPW norms of common igneous rock types. - 3. Norm calculations. - Calculation of the CIPW norm. - Molecular norms. - 4. Calculation of plotting parameters for O'Hara (1968) polybaric phase diagram. - 5. Some representative mineral analyses. - Answers to exercises. - References. Language: English