This text is the first book explicitly designed for the one-term, principles-level course covering both micro and macroeconomics, and canalso be used for two-term or full-year courses where a very concise, focused treatment is desired. This is NOT a cursory "survey" text;rather, it carefully selects and fully explains all of the core topics essential to the principles course with a rigorous and analyticaltreatment of all introductory economic concepts. It presents economics as a unified subject in which the macroeconomics chapters buildon, and flow from, the key microeconomic principles established in the first half of the book.