The idea of a black hole goes back to Laplace or maybe even earlier to Englishman John Michell, referring to these bodies as 'dark stars', way back in 1783. Laplace argued that the largest objects in the universe must become invisible and would hence be dark. When Einstein proposed his general theory of relativity in the early 1900s, Schwarzschild solved the equation (1916) for a spherical star and the solution implied that below a radius (referred to as the Schwarzschild radius), all light and other radiation are trapped inside the star, and it becomes what is called a black hole. With better detection mechanisms, such as the images from the Event Horizon Telescope, the universe of black holes is opening up for astronomical observations and discoveries over all wavelengths. This book covers a wide range of topics related to black holes and their dynamics.