The authors of the essays collected here explore the ways in which late antique groups defined their own socio-political borders and created secure in-group identities by means of discourses about "heresy" and "heretics". A wider definition of "heresy" and "heretics" as real or constructed "internal opposition" and "internal enemies" leads to a new understanding of ancient sources as well as to new comparitve possibilities. Contributors:Holger Zellentin, Eduard Iricinschi, Karen L. King, William E. Arnal, Averil Cameron, Yannis Papadoyannakis, Caroline Humfress, Richard Lim, Annette Yoshiko Reed, Kevin Lee Osterloh, Philippa Townsend, John G. Gager, Burton L. Visotzky, Gregg Gardner, Israel Jacob Yuval