Thornbury's book is organized around several key concepts that are essential to teaching vocabulary effectively. Some of the most important concepts include:

: Both the written (spelling) and spoken (pronunciation) aspects.

The "forgetting curve" is brutal. Thornbury mandates retrieval windows: 10 minutes later, 1 hour later, 1 day later, 1 week later.

Thornbury doesn’t dismiss memorization entirely—he just wants it done intelligently. The classic "L1 on one side, L2 on the other" is weak because it lacks context.