
Once I had finished that, Cullen's "Matrices and linear transformations"[2] was really helpful too. But I wouldn't do Cullen if you're still, as I was, floundering with the concepts of why you're doing this in the first place. It's great once you have those concepts down.
[1]: https://www.amazon.com/All-Mathematics-You-Missed-Graduate/d...
Although an excellent book that covers these things is The Manga Guide to Linear Algebra, by O'Reilley.
Actually, not almost. The author clearly explains this isomorphim in his introduction to matrices.