This book offers a concise and practical introduction to relativistic astrophysics, designed for advanced undergraduate and graduate students, as well as researchers seeking a rapid refresher or a fresh perspective.

Covering the essential concepts of special and general relativity, the book emphasizes their application to modern high‑energy astrophysics. Through numerous worked examples, it connects fundamental theory to the physics of compact objects, relativistic jets, and high‑energy radiation processes, while also introducing the tools used to analyze X‑ and gamma‑ray data.

A distinctive feature of the book is its integrated approach, linking relativistic physics with observational techniques and instrumentation, including a discussion of contemporary data analysis methods. The extensive references provides a gateway for readers who wish to explore advanced topics in greater depth.

Luigi Foschini is a senior researcher at the Brera Astronomical Observatory of the National Institute for Astrophysics (INAF). His research focuses on relativistic astrophysics, particularly relativistic jets in active galactic nuclei, as well as on spacetime physics, with an emphasis on quantum gravity and the nature of time. He is the author or co-author of more than 500 scientific, technical, and popular-science publications, including six books.