---Volume 6 of this landmark edition contains 47 writings—most from the unsettled period in Peirce's life just after he moved from New York to Milford, Pennsylvania, followed shortly afterward by the death of his mother. It begins with interesting remnants of Peirce's correspondence course in logic, by which he hoped in vain to make a living. Other notable selections include the much-heralded "A Guess at the Riddle," Peirce's never-finished yet substantial attempt to draw his wide-ranging philosophical theories into a unified system of thought; his dispute with Edmund Gurney over Gurney's Phantasms of the Living; his attack, under the pseudonym "Outsider," on Spencer's mechanical philosophy; and lengthy excerpts from the report on gravity that led to his forced resignation from the U.S. Coast and Geodetic Survey. These and other writings in this volume reveal Peirce's powerful mind probing into diverse issues, looking for an underlying unity but, perhaps, also looking for direction.