For years, they were the best of friends: Humboldt, a grand, erratic figure, and Charlie, a young man of frenzied and noble longings. But by the 1970s, Humboldt has died a failure, and Charlie's success-ridden life has taken various turns for the worse. Then Humboldt acts from the grave to change Charlie's life by leaving him something in his will.

Now Charlie is middle-aged and his days are cluttered with comic absurdities. A thinker, he longs to come from left field and knock them all dead. But his ex-wife has him enmeshed in lawsuits; he is held in thrall by a sexually-beguiling but unsuitable young woman; he has fallen into the hands of a neurotic mafioso; and his career seems to have ground to a halt. How the gentle but resilient Charlie comes to know how to triumph over his ever more ridiculous tribulations is the great discovery of Humboldt's Gift.