World Hum - that invaluable online magazine of travel news and travel writing - alerted me to a recent review by Paul Theroux of a new biography of V.S. Naipaul.

The two men are closely linked, not only because they are about the last in a long line of novelists who also write travel books, but because of their literary friendship gone bad.

Theroux chronicled it in his book Sir Vidia's Shadow, starting with their meeting in Africa - when the older Naipaul took the young writer under his wing - and ending with Naipaul's abrupt and unexplained break with his prolific and successful disciple.

In the review, which appeared in the London Times, Theroux lists instances of Naipaul's cruelty and selfishness with great gusto, almost glee, as if to say: "See, it's not just me! He really is despicable." You get the feeling that, because of this new biography, he feels vindicated for writing his memoir.

But the review raises the question (in a way that the memoir didn't): If Naipaul really is such a horrible man - which I don't doubt he is - why was Theroux his friend for so long?