Stillwell[1] discusses quaternions in chapters 1 & 2, although the meat and potatoes of the book is more generally about lie groups and lie algebras. It's pitch

Stillwell[1] discusses quaternions in chapters 1 & 2, although the meat and potatoes of the book is more generally about lie groups and lie algebras. It's pitched at a lower level than most books on this topic by restricting attention to the classical matrix groups. [1]https://www.amazon.com/Naive-Theory-Undergraduate-Texts-Mathematics/dp/0387782141/ref=sr_1_1?ie=UTF8&qid=1540144950&sr=8-1 https://www.amazon.com/Naive-Theory-Undergraduate-Texts-Math...