This should be called ""Boston Is A State of Mind"" -- for that is the feeling one has as the last pages of a very entertaining ""Reader"" are turned. Skilful editing has brought together bits from letters, diaries, contemporary records, and modern historians with a feel for the past, so that 17th century, 18th century, 19th century Boston come before one as on a moving screen. From Cotton Mather to John Marquand -- a generous spanese fits the pieces together into a tapestry. Crime and punishment, religion and society, fashions and the servant problem, social change and personalities- all are here. Among the contemporaries (as of each period), Linscott gives us many unknowns, but also adds saver with such writers as Hawthrone, Henry Adams, Henry James, William Dean Howell, and- coming closer to our own times, H.G. Wells, Arnold Bennett, George Santavana. He has drawn generously on such interpretors as Van Wyck Brooks and even Cleveland Amory. Good reading, launching the new City and Country Reader series.