Never let it be said that Pedro A. Sanjuan, the Interior Department's assistant secretary for territorial and international affairs, is one to hide his light under a bushel. The mail brought forth the other day a Xeroxed letter, addressed to "All Interested Parties" and attached to a newspaper article extolling the many talents of Pedro Sanjuan.

The letter, on the Office of the Secretary letterhead, noted that All Interested Parties might find the article, from The Washington Times, "of archival interest." Ditto, presumably, the attached photograph of Pedro Sanjuan, posed dramatically with an etching press that he uses to pursue one of the numerous artistic hobbies detailed in the article.

The article has Sanjuan lavishly praising his boss, Interior Secretary James G. Watt ("one of the most lively and entertaining Cabinet members I ever met") and waxing scornful of a public "that doesn't know anything about national parks, land conservation, what the difference between a wilderness and a park is . . . "

Sanjuan's own background is in the international park, mostly wandering through the protocol wilderness at the State Department. He also did a two-year stint as spokesman for the Arms Control and Disarmament Agency, which might qualify as land conservation.