This book is written from the viewpoint of a deep connection between cosmology and particle physics. It presents the results and ideas on both the homogeneous and isotropic Universe at the hot stage of its evolution and in later stages. The main chapters describe in a systematic and pedagogical way established facts and concepts on the early and the present Universe. The comprehensive treatment, hence, serves as a modern introduction to this rapidly developing field of science. To help in reading the chapters without having to constantly consult other texts, essential materials from General Relativity and the theory of elementary particles are collected in the appendices. Various hypotheses dealing with unsolved problems of cosmology, and often alternative to each other, are discussed at a more advanced level. These concern dark matter, dark energy, matter-antimatter asymmetry, etc.This book is accompanied by another book by the same authors, Introduction to the Theory of the Early Universe: Cosmological Perturbations and Inflationary Theory and is available as a set.Sample Chapter(s)Chapter 1: Cosmology: A Preview (1,644 KB)Chapter 11: Generation of Baryon Asymmetry (701 KB)Contents:Cosmology: A PreviewHomogeneous Isotropic UniverseDynamics of Cosmological ExpansionΛM: Cosmological Model with Dark Matter and Dark EnergyThermodynamics in Expanding UniverseRecombinationRelic NeutrinosBig Bang NucleosynthesisDark MatterPhase Transitions in the Early UniverseGeneration of Baryon AsymmetryTopological Defects and Solitons in the UniverseColor PagesReadership: Cosmologists, advanced undergraduate and graduate students.