The Medford Public Library begins a new season of Monday Morning Mysteries book group meetings, gathering to discuss “Acqua Alta” by Donna Leon. The group will meet on the first Monday of the month from October through June (this month’s meeting is a week later than normal due to the Labor Day holiday on September 4). Next month’s title will be “The Woman in the Library” by Sulari Gentill, to be discussed on October 2.