On donuts and crumbs: A brief history of torus models

A variety of torus models for the infrared emission of AGN has become available in literature over the last decade. This includes radiative transfer models using smooth or clumpy dust and hydrodynamic models. I will review the various types of models that are currently in use and point out their main similarities, differences, and limits when it comes to interpreting observations. Finally, current and future observational challenges for these models are discussed.