This book provides a comprehensive presentation of astroparticle physics and cosmic radiation along with the associated measurement methods in research. After a historical introduction, the astroparticles themselves, their typical interactions, and the relevant measurement techniques are described. A significant portion of the book deals with primary and secondary cosmic radiation. The modern aspects of astroparticle physics are presented in the chapters on cosmology and the early universe. Compared to previous editions, the effects of dark matter and dark energy are described in greater detail. Current results on gravitational waves and exoplanets conclude the book. The text is complemented by many carefully crafted diagrams and illustrations, as well as numerous entertaining cartoons, and largely avoids complicated technical language.