This is a revised and expanded version of the lecture notes for Basic Calculus—other similar courses offered by the Department of Mathematics, University of Hong Kong. This starts from the first semester of the academic year 1998-1999 through the second semester of 2006-2007. The book can serve as a textbook or a reference book for an introductory course on one variable calculus. In this book, much emphasis is put on explanations of concepts and solutions.
By reading the book, students should be able to understand the concepts introduced. Students should also be able to answer questions with justification. At the end of each section (except the last few), there is an exercise. Students are advised to do as many questions as possible.