Order unanimously reversed on the law with costs and motion denied. Memorandum: The court erred in precluding plaintiff's discovery of defendant's karate manual. CPLR 3101 (a) provides, in pertinent part, "There shall be full disclosure of all evidence material and necessary in the prosecution or defense of an action". That language is to be interpreted liberally to require disclosure of facts bearing on the controversy which will assist in preparation for trial. "The test is one of usefulness and reason" (Allen v Crowell-Collier Publ. Co., 21 N.Y.2d 403, 406). Plaintiff established that defendant's karate manual is possibly relevant to prosecution of her personal injury action and thus "material and necessary" within the meaning of the statute.