These notes derive from a course of lectures delivered at the University of Florida in Gainesville during 1971/2.These notes derive from a course of lectures delivered at the University of Florida in Gainesville during 1971/2. Dr Gagen presents a simplified treatment of recent work by H. Bender on the classification of non-soluble groups with abelian Sylow 2-subgroups, together with some background material of wide interest.These notes derive from a course of lectures delivered at the University of Florida in Gainesville during 1971/2. Dr Gagen presents a simplified treatment of recent work by H. Bender on the classification of non-soluble groups with abelian Sylow 2-subgroups, together with some background material of wide interest.These notes derive from a course of lectures delivered at the University of Florida in Gainesville during 1971/2. Dr Gagen presents a simplified treatment of recent work by H. Bender on the classification of non-soluble groups with abelian Sylow 2-subgroups, together with some background material of wide interest. The book is for research students and specialists in group theory and allied subjects such as finite geometries.1. Baer's Theorem; 2. A theorem of Blackburn; 3. A theorem of Bender; 4. The Transitivity Theorem; 5. The Uniqueness Theorem; 6. The case; 7. The proof of the Uniqueness Theorem 5.1; 8. The Burnside paqb- Theorem, p, q odd; 9. Matsuyama's proof of the paqb -Theorem, p = 2; 10. A generalization of the Fitting subgroup; 11. Groups with abelian Sylow 2-subgroups; 12. Preliminary lemmas; 13. Properties of A*-groups; 14. Proof of the Theorem A, Part I; 15. Proof of the Theorem A, Part II.