Nanoscience is not physics, chemistry, engineering or biology. It is all of them, and it is time for a text that integrates the disciplines. This is such a text, aimed at advanced undergraduates and beginning graduate students in the sciences. The book is divided into three parts. Part I (The Basics) is a self-contained introduction to quantum mechanics, statistical mechanics and chemical kinetics, calling on no more than basic college calculus. A conceptual approach and an array of examples and conceptual problems will allow even those without the mathematical tools to grasp much of what is important. Part II (The Tools) covers microscopy, single molecule manipulation and measurement, nanofabrication and self-assembly. Part III (Applications) covers electrons in nanostructures, molecular electronics, nano-materials and nanobiology. Each chapter starts with a survey of the required basics, but ends by making contact with current research literature.