This book provides an introduction to science and scientific thinking for students who have not had much contact with science. It explains what is distinctive about the scientific approach and its product, scientific theories. The emphasis is on quantitative approaches and on showing how the use of number in science greatly extends the reach of the investigative tools. The book is divided into three parts: General Material (what are the problems faced by scientists and the general techniques used to overcome them?); Introduction to Thermodynamics (examples of how theories are constructed); and Introduction to Statistical Analysis (examples of randomness). The book is laid out with a blackboard-style summary on the left-hand pages and text explanations on the right-hand pages. Many examples and assignments are included throughout.