In this decade, the transient universe will be mapped out in great detail by the emerging wide-field multiwavelength surveys, and neutrino and gravitational-wave detectors, promising to probe the astronomical and physical origin of the most extreme relativistic sources. This volume introduces the physical processes relevant to the source modeling of the transient universe. Ideal for graduate students and researchers in astrophysics, this book gives a unified treatment of relativistic flows associated with compact objects, their dissipation and emission in electromagnetic, hadronic and gravitational radiation. After introducing the source classes, the authors set out various mechanisms for creating magnetohydodynamic outflows in winds, jets and blast waves and their radiation properties. They then go on to discuss properties of accretion flows around rotating black holes and their gravitational wave emission from wave instabilites with implications for the emerging gravitational wave experiments. Graduate students and researchers can gain an understanding of data analysis for gravitational-wave data.