Warner, born in 1922 in Chambersburg, Pa., started working at The Herald-Mail Co. in Hagerstown on May 17, 1943, as a reporter. He covered several governmental agencies and the farming community, and he wrote obituaries and general news.
During World War II, he translated letters from Dutch and German families who wrote parents of American soldiers they'd met overseas. Warner had taught himself seven foreign languages - an accomplishment all the more amazing because health problems had forced him to drop out of Hagerstown High School by the 10th grade.
As a youngster, he grew to love the emerging world of science fiction.
"Harry was like a number of other teenagers in the 1930s," said Joe Siclari, a New York teacher who chronicles science fiction history as a publisher and through his Web site, fanac.org. "A lot of these youngsters were very interested in our future and looked at science fiction as a way to speculate and see possibilities," Siclari said.
In 1938, before his 16th birthday, Warner began writing and, using an old mimeograph machine, publishing Spaceways, a magazine for science fiction fans.
In its four years of publication, Spaceways became "one of the most important fanzines of its period and had articles from some of the most important names in the field," Siclari said.
Less than a year after launching Spaceways, Warner began producing Horizons, a personal opinion fanzine - a word meaning fan magazines in science fiction circles.
"Race relations, dangers of the atomic bomb, the speculation about whether atomic power could be used for good - there were discussions in Horizons about many, many of these things," Siclari said.
Like Spaceways, Horizons had only small circulation at first, reaching a few friends in addition to the 75 copies Warner circulated through the Fantasy Amateur Press Association. Warner continued to write Horizons every three months until he died, and it is still being published, Siclari said.
In 1969, Warner's first book, "All Our Yesterdays," was published in hardcover. It was an informal history of science fiction fandom (essentially, conventions, publications and other activities involving fans) during the 1940s. It was reprinted in 1971 in both hardcover and paperback editions. In all, about 4,000 copies were printed, Siclari said.
Warner's second book, "A Wealth of Fable," which covers fandom in the 1950s, first appeared as a three-volume mimeographed edition in the late 1970s. Siclari, who was the publisher, was working with Warner on an illustrated edition that's to come out soon.
Warner also wrote science fiction stories, but most fans knew him for the "interesting and extensive" letters of comment he wrote to fanzines throughout the world, Siclari said. "It was a fan maxim that your fanzine was not complete without a letter from Harry Warner, Jr."
For his work, Warner won several top science fiction awards, said Tim Pratt, an editor at Locus headquarters in Oakland, Calif.
In addition to a Locus award for best fan writer in 1971, Warner was nominated repeatedly for the World Science Fiction Society's Hugo awards - "one of the biggest awards in science fiction given annually by fans," Pratt said.
Warner won the Hugo in 1969 and 1972 as a fan writer, and a third time in 1993 for Best Non-Fiction Book, "A Wealth of Fable," which had been published in hardcover in 1992. In 1995, he won a First Fandom award, a lifetime achievement honor for service to science fiction.
Until he retired in 1983, Warner continued working at The Herald-Mail, seldom, if ever, mentioning these achievements.
Longtime Women's section editor Gloria Dahlhamer, who started on The Morning Herald in 1947 and retired in 1991, said she was surprised when she learned from her brother-in-law, a science fiction fan in California, about Warner's fame. "He never talked about any of that," she said of Warner.