Hey all As usual I can get through the specifics of calculations on books but the big picture escapes me. I'm having difficulty understanding gauge anomalies and cancellations. To be more specific, every book I read talks about Feynman diagrams, giving the impression that gauge anomalies are a perturbative phenomena. On the other hand, the anomaly seems to come from a symmetry of the lagrangian on chiral theories, and I don't see anything perturbation-specific there. I'd appreciate any help, indlucing some interesting references on the subject.