  These lectures give an introduction to baryon chiral perturbation theory. I
show in detail how to construct the chiral effective pion-nucleon Lagrangian in
the one loop approximation. Particular emphasis is put on the physics related
to electromagnetic probes, as manifest in pion photo- and electroproduction,
Compton scattering off nucleons and the electroweak form factors of the
nucleon. Other topics discussed in some detail are the meaning of low-energy
theorems, pion-nucleon scattering, the reaction $\pi N \to \pi \pi N$ and
isospin violation in the pion-nucleon system. The chiral predictions are
confronted with the existing data. Some remaining problems and new developments
are outlined.
