The goal in writing this text is to demonstrate that physical principles can provide great insight into biological systems and processes. The result is a book that addresses life-science students' particular needs for knowledge and problem-solving skills more directly than the standard physics texts available. The book is written for first-year university students in life sciences and environmental sciences. The students are expected to have some background from high-school physics and must have good skills in algebra and trigonometry. Sections of the book that involve calculus are highlighted, giving instructors the option of using calculus if they so choose.