  This tutorial introduces the theoretical and experimental basics of
Electromagnetically Induced Transparency (EIT) in thermal alkali vapors. We
first introduce a brief phenomenological description of EIT in simple
three-level systems of stationary atoms and derive analytical expressions for
optical transmission and dispersion under EIT conditions. Then we focus on how
the thermal motion of atoms affects various parameters of the EIT system.
Specifically, we analyze the Doppler broadening of optical transitions,
ballistic versus diffusive atomic motion in a limited-volume interaction
region, and collisional depopulation and decoherence. Finally, we discuss the
common trade-offs important for optimizing an EIT experiment and give a brief
"walk-through" of a typical EIT experimental setup. We conclude with a brief
overview of current and potential EIT applications.
