by Gilbert Strang
Publisher: Wellsley Cambridge Press 1991
Number of pages: 671
License(s):CC BY-NC-SA 4.0
The book covers all the material of single and multivariable calculus that is normally in a three semester course for science, mathematics, and engineering students. The style is less formal and more personal than the typical text, and it has a definite point of view that helps keep the book to a reasonable length.
Download or read it online for free here: Calculus