The astronomical science dealing with the study of nature and physics of celestial bodies is termed as astrophysics. This book provides readers with a theoretical and observational approach to astrophysics. The invention of sophisticated telescopes and other equipment has brought the universe closer. This is the reason why the field of astrophysics is growing day by day. This book demonstrates the cosmic activities that occur in nature. This book covers different dimensions of astrophysics i.e. observational astrophysics, cosmology, the solar system, stars, planets, galaxies, spectroscopy, theoretical astrophysics, dark matter, neutron stars and high energy astrophysics.