  Einstein's theory of gravitation that governs the geometry of space-time,
coupled with spectacular advance in cosmological observations, promises to
deliver a `standard model' of cosmology in the near future. However, local
geometry of space constrains, but does not dictate the topology of the cosmos.
hence, Cosmic topology has remained an enigmatic aspect of the `standard model'
of cosmology. Recent advance in the quantity and quality of observations has
brought this issue within the realm of observational query. The breakdown of
statistical homogeneity and isotropy of cosmic perturbations is a generic
consequence of non trivial cosmic topology arising from to the imposed
`crystallographic' periodicity on the eigenstates of the Laplacian. The sky
maps of Cosmic Microwave Background (CMB) anisotropy and polarization most
promising observations that would carry signatures of a violation of
statistical isotropy and homogeneity. Hence, a measurable spectroscopy of
cosmic topology is made possible using the Bipolar power spectrum (BiPS) of the
temperature and polarization that quantifies violation of statistical isotropy.
