“Still Waters” by Curt Stager dips into the secret world of lakes,  from Walden Pond to the Dead Sea.  His is a “quietly impassioned argument for the vitality of our lakes”(Kirkus Reviews). “A Naturalist at Large” contains the best essays of Bernd Heinrich.  His topics range  the maple sap harvesting habits of red squirrels to “instant”  opening flowers tests on raven intelligence .  “Chesapeake Requiem” by Earl Swift shows how rising tides are threatening a real American fishing community.