Originally published in 1932, this book discusses the capacity of humans to influence the process of natural selection and thereby control its outcomes.

Preface; Introduction; 1. Mendel's laws of heredity; 2. Cells and chromosomes; 3. Chromosomes and genes; 4. Mapping the genes in the chromosomes; 5. Chromosomes and species; 6. Translocations of genes; 7. Extra chromosomes; 8. Polyploid varieties; 9. Polyploid species; 10. Hybridisation and crossing; 11. Gene mutations; 12. Experimental mutations and transmutations; 13. Genes and characters; 14. Sex; 15. Virgin birth; 16. The smallest living organisms; 17. The gene as the unit of life; 18. Processes of creative evolution; 19. Evolution of man and mind; 20. Speculations; References; Index.