The recognition of the branch of mathematics now known as homotopy theory occurred a few years after the introduction of homotopy groups by Witold Hurewicz in 1935. Since then, thanks to numerous advances by many researchers, it plays an increasingly important role in the expanding field of algebraic topology. This book is designed for the beginning student or newcomer to this branch of mathematics--who has a little knowledge of algebraic topology--to be introduced to the basic principles of homotopy theory. There is enough detail to provide a full understanding of the fundamental ideas and mastery of elementary techniques, which will hopefully lead to more advanced studies in the topic.