Roger D. Fisher, a longtime summer resident of West Tisbury, died on August 25 in Hanover, N.H. He was 90.

A leader in the field of negotiation and conflict resolution, Mr. Fisher was the Samuel Williston Professor of Law, Emeritus, at Harvard Law School where he co-founded the Harvard Negotiation Project. He co-wrote the best-selling book, Getting to Yes: Negotiating Without Giving In in 1981.

A complete obituary will be published in a future edition of the Gazette.