This book helps students to master the material of a standard US undergraduate first course in Linear Algebra. The material is standard in that the subjects covered are Gaussian reduction, vector spaces, linear maps, determinants, and eigenvalues and eigenvectors. Another standard is book's audience: sophomores or juniors, usually with a background of at least one semester of calculus. The help that it gives to students comes from taking a developmental approach-this book's presentation emphasizes motivation and naturalness, using many examples as well as extensive and careful exercises. Author: Jim Hefferon http: //joshua.smcvt.edu/linearalgebraLinear Published, without alternation from the original, under a Creative Commons license CC-BY-SA by Textbook Equity www.textbookequity.com