A general discussion is given of the application of density functional theory of liquids to liquid crystal problems, with particular emphasis to the onset of smectic phases. Hard particle systems have long been used as useful paradigms of liquid crystal behaviour. In this paper we also present recent work on the phase diagram of hard spherocylinders, using a non-local density functional theory of a kind which has been successful in the study of hard sphere thermodynamics. We also discuss the effect of electric quadrupolar forces on the phase diagram of Onsager-like systems.