Thermal radiation arising from random fluctuations lack spatial and spectral coherence. Ability to control thermal radiation and render it partially coherent unlocks solutions to a host of fundamental and technological challenges in thermal imaging, thermophotovoltaics and radiative cooling. Past nanophotonic designs for thermal radiation control are limited by various trade-offs involving spectral selectivity, brightness and directionality. In this thesis, I demonstrate spatial and spectral control of thermal radiation by engineering optical losses, symmetry and topology in a nanophotonic system. First, using the principles of non- Hermitian physics, a loss asymmetric coupled resonator thermal metasurface is designed and experimentally verified to exhibit directional suppression of thermal radiation while maintaining transmission in mid-infrared. Furthermore, I experimentally demonstrate how such a metasurface can be employed to improve image contrast while performing thermal imaging in high temperature environment. Additionally, based on similar design principles, a loss engineered hybrid plasmonic-photonic resonator metasurface is designed to show strong spectral selectivity at elevated temperatures. The metasurface when employed as thermal emitter in a thermophotovoltaic system can improve the overall heat to electricity conversion efficiency. Further, the k-space of metasurface is explored to achieve angle-dependent thermal radiation. Finally, a way to enhance broadband IR absorption is proposed and demonstrated using hyperbolic aligned carbon nanotube films.