2. The Essential First Year, by Penelope Leach. In the eight years between our first and third children, I’m amazed at how many “official” recommendations on child-raising have changed, from the age at which they should start eating solid foods to how long they should ride rear-facing in a car seat. In her new (2010) book on child development, Leach doesn’t always go down to such a microlevel, but does provide a succinct, valuable, reassuring (to me) overview of the latest research. Most coverage of the book has focused on the hot-button issue of sleep-training, but there’s far more to it. Besides, by the time the third child came around, we’d learned to discard any expectations on that particular issue that there is a single “right” answer for all kids.