I want a good reference that discusses properties of octonion algebras, especially over number fields. I'd like to know more about how this generalizes when applying the Cayley-Dickson construction iteratively. I know a good deal about quaternion algebras and so I'm looking to build upon that foundation. I'm interested in geometric interpretations of these, as well as a thorough algebraic treatment. I'm at the end of my PhD so it's okay if it's not all that reader-friendly, but of course if there are 2 books that cover the same material, the more reader-friendly one is better.
I saw some books on Amazon that look good but they are expensive, so I thought I'd seek some opinions from the community. Thanks.