----------------------------------------------------------------- "Mason's Retreat" by Christopher Tilghman Random House, $22 -----------------------------------------------------------------

It's dangerous to include black people as background figures in stories of white families, particularly if the stories are set in the American past. Their presence simply reminds the reader that no matter what misfortunes the white family suffers, the black folks have had it much, much worse.

In "Mason's Retreat," for example, 15-year-old Sebastien Mason is upset by the imminent return of his overbearing father from England and complains to their black maid: "Valerie, you tell me, what's going to happen to Mother?" Why should Valerie care? It's 1938; she lives in a ghettoized section of the Maryland shore; the hopes of her people have been smothered from Day One. The crises of Sebastien Mason seem petty in comparison.

It's to Christopher Tilghman's credit, then, that for most of his first novel we do care about the emotional turbulence in the Mason clan. Tilghman is not a master stylist, but he is an intelligent, insightful writer, and he skillfully conveys the thoughts not only of the Masons, but also of Robert, a black field hand, and Bitsy, a member of the crumbling Maryland aristocracy. With their petty motivations and misinterpretations of others' motivations, these characters often seem unbearably human.