Lactam-bridged dipeptides are useful tools for the introduction of conformational constraint in higher peptides. General methods have been devised for the synthesis of dipeptides having five-, six-, and seven-membered ring constraints (1 ,2 ). This chapter will focus on four synthetic paths from protected chiral a-amino acids to lactams that involve intramolecular alkylation, intermolecular alkylation, intramolecular acylation, and condensation with formaldehyde for a one carbon unit insertion.