Micah Mortimer, the strikingly unproactive protagonist of Anne Tyler’s 23rd novel, is a man of such unswerving routine that his rare moments of whimsy — slipping into a foreign accent on Mondays when the week turns to floor-cleaning and ‘zee dreaded moppink’ — come to seem like unfathomable caprice. Indulging a sudden hankering for a takeaway barbecue is as wild to him as one of Hunter S.