What you should know

What Every Computer Scientist Should Know About Floating-Point Arithmetic
What Every Programmer Should Know About Memory
What every programmer absolutely, positively needs to know about encodings and character sets to work with text
Latency Numbers Every Programmer Should Know
What every programmer should know about time
What Every Programmer Should Know About Races
What Every C Programmer Should Know About Undefined Behavior
What every data programmer needs to know about disks