The Sunday of Life, the late Raymond Queneau's tenth novel, was first published in French by Gallimard in 1951 and is now appearing for the first time in this country. In the ingenuous ex-Private Valentin Bru, the central figure in The Sunday of Life, Queneau has created that oddity in modern fiction, the Hegelian naif. Highly self-conscious yet reasonably satisfied with his lot, imbued with the good humor inherent in the naturally wise, Valentin meets the painful nonsense of life's adventures with a slightly bewildered detachment.