Foreign publications free from customs duty

§ 4060. Foreign publications free from customs duty (a) Printed matter other than books received in the mail from foreign countries under the provisions of postal treaties or conventions are free of customs duty. (b) When books which are admitted to the international mail under the provisions of the Universal Postal Union Convention are subject to customs duty, they may be delivered by the Postmaster General as addressed under such regulations for the collection of duties as may be agreed upon by him and the Secretary of the Treasury.