The book is designed for students taking introduction and intermediate thermodynamics courses in degrees and HNDs in Mechanical Engineering, Chemical Engineering and Process Engineering. The text provides a progressive development of ideas together with progress questions placed at regular intervals throughout the material. In the main, these questions are designed to be worked through before the student moves on through the text. This allows the assimilation of material at a rate which suits the individual. The text lays down, clarifies and develops the early concepts of thermodynamics in an engineering context. Wherever possible the use of calculus is avoided or separated from the main text in a manner which enhances the simplicity of presentation. SI units are used throughout and Imperial conversions are listed for reference. This book should be of interest to introductory/intermediate undergraduates on engineering courses.