CFT is a new constraint system providing records as logical data structure for constraint (logic) programming. It can be seen as a generalization of the rational tree system employed in Prolog II, where ner-grained constraints are used, and where subtrees are identiied by keywords rather than by position. CFT is deened by a rst-order structure consisting of so-called feature trees. Feature trees generalize the ordinary trees corresponding to rst-order terms by having their edges labeled with eld names called features. The mathematical semantics given by the feature tree structure is complemented with a logical semantics given by ve axiom schemes, which we conjecture to comprise a complete axiomatization of the feature tree structure. We present a decision method for CFT, which decides entailment and disentailment between possibly existentially quantiied constraints. Since CFT satisses the independence property, our decision method can also be employed for checking the satissability of conjunctions of positive and negative constraints. This includes quantiied negative constraints such as 8y8z(x 6 = f (y; z)). The paper also presents an idealized abstract machine processing negative and positive constraints incrementally. We argue that an optimized version of the machine can decide satissability and entailment in quasi-linear time.