Ecologists now recognize that the dynamics of populations, communities, and ecosystems are strongly affected by adaptive individual behaviors. Yet until now, we have lacked effective and flexible methods for modeling such dynamics. Traditional ecological models become impractical with the inclusion of behavior, and the optimization approaches of be "[A] welcome addition to the esteemed monographs in [the] Population Biology series from Princeton University Press."---Darcy Visscher, The Quarterly Review of Biology