Foundational skills — reading grain, dimensioning rough lumber, glue-ups, and precision marking.
Why a board chips out on one face and planes cleanly on the other. The difference between rift, flatsawn, quartersawn, and reading direction.
The process for turning a rough-sawn board into a flat, square, dimensioned piece ready for joinery.
Why panels cup, bow, and twist during glue-up, and the techniques that fix every common failure.
Why a pencil line is not good enough, and the system of squares, gauges, and knives that gets joinery to slip-fit.