The fate of atoms in strong laser fields in considered in this chapter. The concept of multiphoton ionization (MPI) of multielectron atoms is first considered, and the theory of MPI within the rubric of lowest-order perturbation theory is detailed. The key nonperturbative approach to calculating ionization rates, the strong field approximation (SFA), is then developed. The Keldysh approximation is utilized and various forms of the ionization rate of an atom in the intense laser field are derived from the SFA. The important concept of tunnel ionization is then discussed. Models of tunnel ionization are successively derived, starting with the simple hydrogen atom and concluding with derivation of the PPT/ADK formula for tunnel ionization of complex atoms. The limit of tunneling at high fields in the barrier suppression realm is explored. The phenomena of nonsequential double ionization and above-threshold ionization (ATI) are each considered in turn. Detailed aspects of ATI such as peak suppression, resonant enhancement, and rescattering are scrutinized in the chapter, which concludes with a survey of the physics of ionization stabilization and relativistic effects.