A mathematics professor from Saint Michael's College is the author of this free online textbook about linear algebra. Being just shy of 450 pages, the book is very comprehensive and of high quality. It gives an excellent introduction into topics such as vector spaces, linear systems, and determinants, and the author is quite good at defining a consistent notation throughout the book. Each chapter has several examples that demonstrate the concepts, concluding with exercises to be solved by the reader. Solutions to the exercises are given in a separate file. [CL]