The dead woman had no problems in her emotional and sexual life. Her lover, Trader Faulkner, gives Mike a plausible account of the health of their relationship. Mike also interviews Jennifer's doctor, Hi Tulkinghorn, and her boss, Bax Denziger, a physicist at the Institute of Physical Problems, where Jennifer worked in the Department of Terrestrial Magnetism attempting to measure the age of the universe. As he did to such extraordinary effect in ''London Fields,'' the closest of his books in theme and temper to ''Night Train,'' Amis employs ideas drawn from astrophysics as a conceptual backdrop to the drama. Hawking understood black holes because he could stare at them.
Black holes mean oblivion.
A tone of deep sadness, of grief even, has always been apparent in his work, lending depth and edge to a prose crackling with wit and invention. That same elegiac tone is present in ''Night Train,'' but this time it is unrelieved by the antic flamboyance of the earlier work. Night Train'' is at heart a work of dark romanticism, a tale of possession. Jennifer Rockwell, soul of the world, can no longer look upon that world. Mike Hoolihan, salt of the earth, comes to understand why.