C0NTENTS Introduction.................................................................................................................... 3 § 1. A subring theorem for free nilpotent Lie rings................................................. 10 § 2. The Lie ring associated with a free nilpotent group....................................... 20 § 3. Subrings which are associated with subgroups............................................ 27 § 4. Subgroups having the same Lie subring......................................................... 43 § 5. The Lie ring associated with a free group........................................................ 47 § 6. The full commutator group.................................................................................. 51 § 7. The Lie ring associated with a free group of exponent 3.............................. 66 Reference....................................................................................................................... 70