THE DARK by John McGahern. 191 pages. Knopf. $3.95.
"Ireland," said George Moore, "is a fatal disease." Author John McGahern gloomily agrees. In The Barracks, a first novel of keening intensity, he called the disease cancer and described how a woman dies of it in a squalid Irish village. In The Dark, his second novel, he calls the disease despair and describes how it drains and ultimately destroys a young man of talent.
Mahoney is his name, and his despair is the nth term in a series of miseries. He is born poor. He loses his mother when he is nine. He hates...