This introductory textbook has been designed by a team of experts for elementary university courses in astronomy & astrophysics. It starts with a detailed discussion of the structure & history of our own Galaxy, the Milky Way, & goes on to give a general introduction to normal & active galaxies including models for their formation & evolution. The second part of the book provides an overview of the wide range of cosmological models & discusses the Big Bang & the expansion of the Universe. Written in an accessible style that avoids complex mathematics, & illustrated in colour throughout, this book is suitable for self-study & will appeal to amateur astronomers as well as undergraduate students. It contains numerous helpful learning features such as boxed summaries, student exercises with full solutions, & a glossary of terms. The book is also supported by a website hosting further teaching materials.