Some books have a success partly because of their worth but also because they seem to hit the right note for the zeitgeist at their moment of publication. One thinks of Lucky Jim, The Virgin Soldiers and The L-Shaped Room. Kingsley Amis has been wise to resist the temptation to write a Son of Lucky Jim, but Leslie Thomas and Lynne Reid Banks have both succumbed. There is even a Y-shaped house in Two is lonely, being built by solidly masculine, 44-year-old Andy whom Jane Graham is considering as a 'daddy' for her 8-year-old, illegitimate son, David. Before making up her mind to marry Andy, Jane goes off to visit an earlier love, Toby, now living in the uncomfortably warm climate of Israel, where the sharav is blowing and the Six-Day War is about to flare up. Then … But this is the kind of book that depends more...