'This Is the Zodiac' The letter received yesterday by The Post, postmarked in Brooklyn and addressed to the Editor, arrived in the morning mail.

Galleys of books for review consideration should be addressed to the "Editor of the Book Review" three to four months in advance of publication.

Letters should be addressed to Letters to the Editor, Magazine, The New York Times, 620 Eighth Avenue, 6th Floor, New York, NY 10018.

Letters should be addressed to The Editor, Connecticut Weekly, The New York Times, 229 West 43d Street, New York, N.Y. 10036.

The letter to The Post was described by the police and federal authorities as containing a small amount of a powdery substance and it was addressed to "the Editor of The New York Post."

They can be sent to London or Washington and should be addressed to the Editor.