Baryonic spectra from multichannel amplitudes

Ongoing and future experiments at precision electromagnetic facilities around the world have ushered in a renaissance in hadronic reaction theory. These high-statistics experiments offer comprehensive kinematic coverage and a large number of new polarization observables -- including the exciting prospect of a complete measurement for several reactions -- and will provide stringent constraints on reaction parameterizations and models. The recent developments promise to shed new light on the physics of baryon resonance spectroscopy, providing a window into the non-perturbative regime of QCD. Though the reaction theory is a mature field, complex phenomenological and theoretical challenges remain. Phenomenologically, amplitudes must be determined in a manner consistent with unitarity while fitting a multichannel set of unpolarized and polarized observables. The {\sc said} amplitudes for $\pi N\to\pi N$ and $\pi N\to\eta N$, as a model example of such a phenomenology, are discussed in some detail and compared with other parameterizations. Efforts to enlarge the said approach to describe the photo- and hadro-production globally have recently yielded promising developments, including a simultaneous description of $\pi-$ and $\eta-$ photoproduction amplitudes. Theoretically, multichannel, unitary dynamical models have recently undergone significant developments. An overview of these approaches are considered by comparing results from several recent calculations.