Ruby Under the Microscope: http://patshaughnessy.net/ruby-under-a-microscope

The CS Detective: https://nostarch.com/csdetective

Mazes for Programmers: http://www.mazesforprogrammers.com/

A Curious Moon: https://bigmachine.io/products/a-curious-moon/

xchg rax,rax: https://www.xorpd.net/pages/xchg_rax/snip_00.html