This book is written primarily for upperlevel undergraduates and graduate students in engineering and professionals in industry. The book offers an accessible broad-based coverage of the basics through advanced applications of microfluidics and nanofluidics.  After a review of key aspects in classical fluid mechanics and heat transfer (Chapter I), the reader is introduced to microfluidics (Chapters II and III) and nanofluidics (Chapters IV and V), with a discussion of math modeling and computer simulation (Chapter VI) rounding out the book. The main goal is to teach a solid knowledge base of the fundamentals and to acquire modern application skills. Furthermore, this six?]chapter exposure should provide students with a sufficient background for advanced studies in these fascinating and very future?]oriented engineering topics, as well as for expanded job opportunities. The author offers a consistent 50/50 physics?]mathematics approach when introducing new material, illustrating concepts, showing flow visualizations, and solving problems. The problem solution format follows strictly: System Sketch, Assumptions, and Concept/Approach --before starting the solution phase which consists of symbolic math model development, numerical solution, graphs, and comments on physical insight.  A solutions manual is planned to accompay the book.