Baryon resonances in large Nc QCD

We review the current status and present open challenges of large $N_c$ QCD baryon spectroscopy. After introducing the $1/N_c$
expansion method we first shortly revisit the latest achievements for the ground state properties. Next we discuss the
applicability of this method to excited states, presenting two different approaches with
their advantages and disadvantages. Selected results for the spectrum and strong and electromagnetic decays are described.
We also present further developments for the applicability of the method to excited states, based on the qualitative compatibility
between the quark excitation picture and the meson-nucleon scattering picture. We show that a quantitative comparison between results obtained from
the mass formula of the $1/N_c$ expansion method and quark models brings convincing support to quark
models and shortly discuss the implications of different large $N_c$ limits. We stress that the SU(6) spin-flavor structure of large $N_c$ baryon
allows a convenient classification of highly excited resonances into SU(3) multiplets and predicts mass ranges for the missing partners.