This book provides a comprehensive and pedagogically oriented introduction to modern cosmology, bridging the gap between introductory textbooks and the research literature. Developed from graduate courses and advanced schools, it combines physical insight with a solid mathematical foundation and is suitable for both self-study and classroom use.

The second edition expands the historical account of cosmology, including translated excerpts from seminal papers, and offers updated discussions of cosmological distances, the Hubble tension, and thermal distributions in an expanding Universe. The opening chapters are structured to support a basic course in cosmology.

Beginning with the observational foundations of the expanding Universe and its principal components, the book develops the theoretical framework from Newtonian arguments to the Friedmann–Lemaître–Robertson–Walker geometry, the Friedmann equations, and the ΛCDM model. It then examines the microphysics of the early Universe, including kinetic theory, particle decoupling, relic abundances, nucleosynthesis, and recombination.

Further chapters provide a self-contained treatment of cosmological perturbations, inflation, structure formation, and Cosmic Microwave Background anisotropies and polarization. Numerous explicit derivations, intermediate steps, and selected exercises guide readers through the subject and connect fundamental theory with modern cosmological observations.

Oliver Fabio Piattella (OFP) obtained his Bachelor’s degree in Astrophysics (2003), Master’s degree (2006), and PhD (2010) in Cosmology and Gravitation from the University of Insubria (Como, Italy), under the joint supervision of Professors Ugo Moschella and Alexander Yu. Kamentchik. During his PhD, he carried out part of his research at the Institute of Gravitation and Cosmology (ICG) of the University of Portsmouth (United Kingdom), collaborating with Professor Marco Bruni.

In 2010, he was a junior postdoctoral fellow of CNPq under the supervision of Professor Júlio C. Fabris; in 2011, he served as a visiting professor and subsequently as an associate professor at the Universidade Federal do Espírito Santo (UFES, Vitória, Brazil). From September 2018 to March 2020, he was a CAPES/Humboldt fellow at the Institute for Theoretical Physics of Heidelberg University (Germany), hosted by Professor Luca Amendola.

In 2016, he contributed to the design and launch of the PPGCosmo doctoral program, where he served as vice-coordinator. From 2022 to 2024, he was a researcher at the Department of Science and High Technology (DiSAT) of the University of Insubria, where he currently holds the position of Associate Professor.

His main research areas are Cosmology, Astrophysics, and Gravitation, with particular interest in dark matter and dark energy problems, modified gravity theories, inflationary models of the Universe, and black hole astrophysics.