"At nine o'clock that night the wind dropped and with it fell my heart . . ." Having ignored the warnings on the cover - well, almost every thriller comes festooned with the words "gripping" and "harrowing" nowadays, doesn't it? - this unwary reader was hooked almost at once by Frank Delaney's sharply-honed fourth novel, and I can tell you now that there is not a single disappointment among its 478 pages, except perhaps that there is no page 479. The plot concerns one Nicholas Newman, a successful architect who, following the brutal murder of his lover, is led into a poisoned jungle of evil whose roots are in the Holocaust and whose branches curl mercilessly around his own throat. Unputdownable is an ugly word, but if ever a thriller was unputdownable, this is it.