UPDATE, Thursday: Found safe.
Caleb Jacoby, 16, an 11th grader at the Maimonides School, has not been seen or heard from since 12:30 p.m. yesterday.
He's 5'11" and 140 lbs., and was last seen wearing navy chinos, a navy polo shirt, a brown winter jacket with a hood, white socks and brown sneakers or shoes.
Police urge anybody with information about his whereabouts to contact them, at 617-730-2222.
Jacoby is the son of Globe columnist Jeff Jacoby.