Saha Ionization Equation -- A Century of Hindsight

We revisit the Saha ionization equation almost one hundred years after it was written down. The equation, which is considered as the harbinger of modern Astrophysics, is loaded with remarkable insights -- some stated, some implied. We would like to unravel the overt and covert aspects of the equation that straddle a remarkable canvas of interdisciplinary concepts. These include early application of the emerging ideas of the Bohr model of the atom, spectroscopy, yet-to-be formulated theory of chemical reactions, and indeed of deep aspects of equilibrium and non-equilibrium statistical mechanics.