Python exception handling uses try/except/else/finally blocks. Catch specific exceptions, never bare except. The else block runs when no exception occurs. Finally always runs for cleanup.
Custom exceptions inherit from Exception: class InsufficientFundsError(Exception): pass. They provide semantic error handling and can carry context data.
Exception chaining with raise ... from ... preserves the original traceback. Context managers provide another cleanup mechanism.
Best practices: catch specific exceptions, use custom exceptions for business logic, log exceptions with traceback, and never silently swallow errors.
The warnings module alerts about non-fatal issues. assert statements catch programmer errors during development but are stripped in optimized mode.