As tenaciously as the Guelphs and the Ghibellines, the boys of the villages of Longevernes and Velrans perpetuate a vendetta of hundreds of years. With the ripping of smocks and the clatter of sabots, missiles and invectives fly--the Longevernes have ""flabby balls"" and the Velrans ""awl have hary asses."" Prefatory chapter heading quotations from Rabelais do not justify the publisher's comparison, and the referral to Mark Twain seems altogether undeserved. . . . Under the leadership of Lebrac the war goes on from day to day and week to week; as buttons come off, there are some literal rearguard actions as the vanquished emerge with bottoms bared; a closing scene, the treason trial of one of theirs, a cripple, with the punitive reprisals, is quite brutal. But for the most part, this ""classic"" which appeared in France more than thirty years ago is resoundingly dull--and for all its peasant vigor, la guerre n'est pas finie for a long, long time.