It's always exciting to read a debut novel when it displays as much promise as "The Walking People." A tale of two families, author Mary Beth Keane's new novel moves deftly between Ireland and the U.S. in this tale of family secrets and the steep price they exact. When timid Greta Cahill leaves Ireland for a new life in America she succeeds beyond her wildest dreams. She falls in love, raises a family and earns a living, but at a great cost - a long interred secret means she must always keep her American life separate from her Irish past, even among the people she is closest to. Keane has written a novel in the old manner, full of plot points and reversals and revelations, and she's done so with so much skill that there can be no doubt that her voice will only strengthen and dazzle with each new book. Houghton, $25.