The invention relates to a zinc finger polypeptide library in which each polypeptide comprises more than one zinc finger which has been at least partially randomized, and to a set of zinc finger polypeptide libraries which encode overlapping zinc finger polypeptides, each polypeptide comprising more than one zinc finger which has been at least partially randomized, and which polypeptide may be assembled after selection to form a multifinger zinc finger polypeptide.