WHAT'S in a museum? To some, the idea conjures up visions of cobwebbed corners, specimens smelling of formaldehyde, dioramas full of dusty dinosaurs.

A museum should have museum things in it. Old things. Dead things. Obsolete things. Rare things. Unusually pretty things. Pathetically ugly things. Things to learn from, things to talk about. A museum illuminates the unknown, sheds new light on the known, and turns its beacon back on you.

A museum can be a historic house where a wealthy matron lived, and visiting it is a voyeur's experience. It can be a mine of military memorabilia, or a local historical society's collection of things passed on from mother to daughter, making you feel as if you're looking at your own history.

It can be a grand art gallery of world-class collections overwhelming you with beauty after beauty. Or it can be a rather small gallery, a gentleman's collection in what was once a private home, appealing to you in its sheer digestibility; that it can be "done" in less than an hour on a quiet afternoon.

But it's a cliche that museums are like forgotten novels on the top shelf that need the dust blown from their covers. The museums in the Washington-Baltimore-Richmond area are very much alive.