by ALISTAIR COOKE
ALISTAIR COOKE is taking a leave of absence for three months and is going on a holiday round the world. Happily for listeners, he confesses: 'I should feel bound and gagged if I were asked to desert my first love-broadcasting -for even three months.' So his weekly Letter from America has become Letter from the World, and may be broadcast from Geneva, Addis Ababa, Beirut, and many other places along his route through Turkey, India, Thailand, Hong Kong, the Philippines, and Japan.