Elizabeth Wassell's fifth novel Sustenance is an opulent tale of food and love. Who is Lily Murphy? She has platinum-blonde hair but dark eyes; she was born in New York to the daughter of a ballet dancer, but educated in England, and now she is a restaurant critic in Dublin.   In Sustenance, we journey into Lily's world of sumptuous meals, but also into her troubled past, where the dinner table was heavy with menace. We also meet Nicholas Savage, the brilliant chef with whom she falls in love, but who, like Lily, harbors a dark secret. In scenes from Dublin to Belfast, Paris to Nice, and London to New York, Lily's world of restaurants, and her milieu of eccentric friends, lovers and the occasional enemy, is vividly portrayed.   This mouth-watering novel - full of passion, pathos and startling descriptions of food - explores the mysterious realms of the heart and mind.