Katherine Anne Porter's essays and occasional pieces, unlike her fiction, are not models of ingenuity and craft, nor do they have the beautiful solidity of her best writing. The memorable cadences of Flowering Judas and Noon Wine disappear when she leaves her imaginary and near-perfect world and enters the arena of criticism or biographical sketches or records her impressions of passing events. Although she speaks always with directness and sometimes with desolating accuracy, only a quarter of the contents of this hefty collection covering four decades of marginal activity has the mastery of style associated with her name. The showpieces are ""Gertrude Stein: Three Views,"" a lethal bit of deadly mimicry which caused a furor when it was published shortly after Miss Stein's death, and ""A Wreath for the Gamekeeper,"" another bloody exhibit introduced during the recent obscenity trial concerning Lady Chatterley's Lover, Miss Porter appearing as star witness for the prosecution: Lawrence ""wished to be the godhead in his dreary rigmarole of primitive religion... but must be the passive female too. Until he tires of it, and comes up with a fresh set of rules for everybody."" Miss Porter is tart, chatty, descriptive (see the passages on Mexico), very much her own woman throughout. A mixes blessing.