It is important to lay a solid foundation in mathematics if a student is to be competitive in today's global market. The importance of algebra, in particular, cannot be overstated, as it is the basis of all mathematical modelling used in applications found in all disciplines. Traditionally, the study of algebra is separated into two parts, Linear algebra I and Linear algebra II. This textbook, Linear Algebra I, is the first part, written in a clear and concise manner, making no assumption of prior algebra experience. It carefully guides students from the basics to the more advanced techniques required to be successful in the next course. This text is, by far, the best Linear algebra I textbook offered under a Creative Commons license. It is written in such a way as to maintain maximum flexibility and usability. A modular format was carefully integrated into the design. This textbook will effectively enable traditional or nontraditional approaches to linear algebra I. The goal of this textbook is to help the learners learn Linear algebra intelligently for solving a wide variety of mathematical and physical problems.