Ask HN: What is one great, easy-to-read book about CS that is not widely known?

Data structures and algorithms: &quot;Competitive Programmer’s Handbook&quot; by Antti Laaksonen (https:&#x2F;&#x2F;cses.fi&#x2F;book&#x2F;book.pdf).<p>Operating systems: &quot;Operating Systems: Three Easy Pieces&quot; by Remzi H. Arpaci-Dusseau and Andrea C. Arpaci-Dusseau (http:&#x2F;&#x2F;pages.cs.wisc.edu&#x2F;~remzi&#x2F;OSTEP&#x2F;).