These guides are reference essays, not tutorials. They assume you have already met the standard somewhere — in a stack trace, a file that opened as gibberish, a regex that lost track of a character with an accent — and want a precise, undecorated account of what is going on underneath. Each piece is grounded in real codepoints, real byte sequences, and real history: Joseph Becker's 1988 proposal, the surrogate range that UTF-16 reserves between U+D800 and U+DFFF, the Zero Width Joiner at U+200D that turns four people into one family.
Read them in any order. The encoding piece pairs naturally with the codepoints-vs-characters piece; normalization pairs with the bidirectional text piece because both involve text that looks one way and behaves another. When a guide references a specific codepoint or tool, follow the link — the site is built to be cross-referenced, the way a good reference book is.