<p>Allowing herself several months to unwind, Dervla Murphy, at sixty, set off on a three-thousand-mile bike ride from Kenya to Zimbabwe via Uganda, Tanzania, Malawi and Zambia. She soon realized that, for travellers in search of tranquillity, Africa is best avoided. Beguiled by the loquacious people she met, she was nevertheless preoccupied by their immense hardships: the devastating effects of AIDS (or ukimwi as it's called in Swahili); drought...