This guide covers planning, building, and finishing an IKEA BILLY office built-in makeover, the kind that reads like custom cabinetry instead of a row of flat-pack bookcases pushed against a wall. Four decisions largely determine whether it works: layout planning, base construction, wall anchoring, and trim work. This guide sticks to the bookcase-and-cabinet wall itself: the shelving, cabinets, base, and trim. It doesn't cover building a matching desk, since a built-in desk is its own carpentry...