Out East captures the enduring appeal of shingled houses, modernist oceanfront designs, artists’ compounds, and Montauk surf shacks. Jennifer Ash Rudick, a long-time Southampton resident, leads an insider’s tour of more than 25 houses, cottages, and pool houses. Tria Giovan, a Sag Harbor–based photographer, captures extraordinary gardens, verandas, lakeside pavilions, farmhouses, and converted barns.