The classical approach to showing the parallel between theorems concerning Lebesgue measure and theorems concerning Baire category on the real line is restricted to sets of measure zero and sets of first category. This is because classical Baire category theory does not have an analogue for the Lebesgue density theorem. By using ${\mathcal I}$-density, this deficiency is removed, and much of the structure of measurable sets and functions can be shown...