A lot of useful ideas are pretty timeless, and for learning fundamental technical content, a _good_ book is worlds better than a collection of blog posts and wi

A lot of useful ideas are pretty timeless, and for learning fundamental technical content, a _good_ book is worlds better than a collection of blog posts and wikipedia pages. I remember when I was learning about quaternion math, I spent a few days googling around, but often different authors would use different notational conventions, or have different assumptions (e.g. whether the coordinate system is right or left-handed), so the math would be subtly different. Not to mention the ones that were just flat-out wrong. So I went to the library, browsed through several books to find one that seemed most relevant, and ended up checking out "Quaternions and Rotation Sequences" from J Kuipers. Having a single well-thought-out book that walked from the basic background all the way through, with consistent notation, was way easier to follow than the scattershot collection I'd found online. So in general I'd say if you're optimizing for the most up-to-date information on a subject that's changing quickly, looking online is probably your best bet. If you want to learn something more foundational and can find a good book about it, I'd definitely go for that.