In a legal decision with potential implications for the publishing industry, a federal judge has ruled that a publisher breached its contract with an author by failing to print enough copies of his book, by refusing to advertise the book, and by letting the book go out of print.

But U.S. District Court Judge Charles L. Brieant, in a ruling released Tuesday, dismissed allegations of interference against codefendant E.I. du Pont de Nemours & Co., the subject of the book.

Gerard Colby Zilg, the author of "Du Pont, Behind the Nylon Curtain," claimed that financial prospects for the 1974 book were damaged irredeemably because his publisher, Prentice-Hall Inc., was intimidated by Du Pont interests.

Zilg said that, although the decision "at least vindicated my charges that the book was suppressed," he is considering an appeal because Du Pont was cleared of wrongdoing.

The case hinged on a July 25, 1974, telephone call from a Du Pont public relations man to an editor at Book of the Month Club Inc. The club dropped plans to carry the book after the Du Pont official said several persons at his company had read a manuscript of the book and found it "scurrilous" and "actionable."

Brieant described Zilg's book as "shrill," "polemical," and "sloppy," among other things.

However, the judge said that Prentice-Hall, "having accepted" the manuscript, "had a duty to perform under the agreement."

Prentice-Hall's "failure to perform was so significant as to constitute a breach of contract," said Brieant, who granted Zilg damages of $24,250, the amount he figured the author lost from the publisher's actions. Zilg had sought $350,000 in compensatory and $1 million in punitive damages.

Special correspondent John Kennedy contributed to this article.