Ask HN: Best Textbooks worth owning on various subjects?

I still have two major textbooks on my bookshelf - and I refresh them every few years. Having been out of education 15+ years I'm now seeing the need to broaden my base.

The two I come back to are:

1. Computer Architecture, a Quantitative Approach.

2. The Molecular Biology of the Cell.

Both are surprisingly accessible texts. And full of detail.

Any others that people would recommend? I'd love to get a refresher on Linear Algebra, Western Philosophy, AI.