Under 19 U.S.C. 1500(b), Customs shall under rules and regulations prescribed by the Secretary of the Treasury fix the final classification and rate of duty applicable to merchandise. The Secretary provides for tariff rulings before the entry of goods by regulations authorizing ruling letters setting tariff classifications for particular imports. This ruling letter represents the official position of the Customs Service. A ruling letter is to be applied only with respect to transactions involving articles identical to the sample submitted or to the articles whose description is identical to the description set forth in a ruling letter (177.9(b)(2)). A letter is subject to modification or revocation without notice to any person to whom the letter was addressed (177.9(c)). The regulations clearly state that no person should rely on such a letter or assume that the principles in a letter will be applied in any other transaction. Any of the 46 Customs offices may issue ruling letters. Most letters do not have any reasoning attached, but some do set out a rationale in some detail. Mead imports day planners. Between 1989-1993 Customs, treated day planners under the “other” category of items in subheading 4820.10 and they were thus free of duty. Customs decided to change that position in 1993 and reclassified Mead’s products as bound diaries subject to a tariff. Mead protested, and a more detailed letter was issued but never published. The letter considered the two definitions of diary from the dictionary and concluded that Mead’s products were bound diaries. Mead (P) challenged this classification, and the Court of International Trade affirmed. The Federal Circuit reversed holding that the letter was not entitled to Chevron deference because it was not issued after notice and comment rulemaking.