This volume provides a combination of a solid foundation of the core physical concepts of cosmology and contemporary astronomical observations. The text is designed for advanced undergraduates or beginning graduate students and assumes no prior knowledge of general relativity. An emphasis is placed on developing the students' physical insight rather than losing them with complex maths. An approachable writing style and wealth of fresh analogies from everyday physics are used to make the concepts of cosmology more accessible. The book not only includes contemporary major developments in cosmology, like the cosmological constant and accelerating universe, but also anticipates key developments expected in the next few years, such as detailed results on the cosmic microwave background. A wide range of carefully developed problems is provided that are suitable for students from a range of backgrounds at the junior/senior level.