Alice Hoffman may be the most uneven writer in America. A trip through her enormous body of work — for adults and young people — is a jarring ride, from the loveliness of “Illumination Night” to the schlockiness of “The River King.” Hang on tight and you’ll swerve from the quiet power of her short stories in “Local Girls” to the groaning hokiness of “The Ice Queen.” In bestseller after bestseller, she explores women’s subjects and feminist themes, especially ancient and modern expressions of witchcraft.