In a corner of Harlem hemmed in by a steep ravine within Jackie Robinson Park and the Harlem River, a residential enclave is undergoing a renaissance. Among a string of four recently finished sale buildings, a seven-story, six-unit condominium has begun work at 306 West 148th Street, between Bradhurst Avenue and Frederick Douglass Boulevard. Conceived by Bottom Line Construction & Development (no comment), the 10,000-square-foot building is to be called The Baldwin after the eminent Harlem-born novelist, poet, playwright and social critic, James Baldwin. Channeling the author’s spirit, the condo will capture in its residences “the sophisticated details and artistic flare of contemporary Harlem living.”