This book presents a treatment of single variable Calculus designed as an introductory tertiary level mathematics textbook for engineering and science students. The subject matter is developed by modelling physical problems, some of which would normally be encountered by students as experiments in a first year physics course. The solutions to these problems provide a means of introducing mathematical concepts as they are needed. The book presents all of the material from a traditional first year calculus course, but it will appear for different purposes and in a different order from standard texts. The book rationale is that mathematics should be introduced in a context that is tailored to the needs of the audience. Each mathematical concept is introduced when it is needed to solve a particular practical problem, so at all stages, the student should be able to connect the mathematical concept with a particular physical idea or problem. Every chapter includes examples and exercises, with additional examples and answers at the endof the book.