It’s not only parents whose babies sleep who have the energy to write books on the topic (Letters, 7 September). Forty years ago, I wrote a book for insomniac parents, Sleepless Children, precisely because both our offspring were awful sleepers. Daily at 5am – after yet another constantly disturbed night – I’d get up, caffeinate myself, sit a wide-awake baby on my lap, and write for an hour, while my wife grabbed a burst of child-free sleep before the day really started. David Haslam Dorchester