Years of Effort Produce 600-Page Celtic Epic : Kathryn Cocquyt started off researching mouth bits for horses and ended up with a saga about 1st-Century warriors.

What triggers an idea, fires the imagination and keeps a writer plotting and plodding for years?

Kathryn Cocquyt invested years of research and four more years writing “Celtic Heart” a 600-page historical novel set during the Roman invasions of the British Isles in the 1st Century A.D. The author, who raises horses in the Simi Valley, was researching an alternative to metal mouth bits when she discovered material about the equestrian skills of the ancient Celts.

She was intrigued and began the saga of the Celtic warriors who struggled to preserve their culture against the encroachment of the Roman Empire.

Cocquyt, who is also the author of “Little Freddie at the Kentucky Derby” and “Little Freddie’s Legacy,” will sign “Celtic Heart” at 5 p.m. Saturday at Barnes & Noble, 4360 E. Main St., Ventura.

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A discussion group focusing on books of interest to the gay and lesbian community will meet at 7:30 tonight at Barnes & Noble.

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Mysteries to Die For, 2940 Thousand Oaks Blvd., Thousand Oaks, will offer lunch, prizes and author appearances at a Christmas celebration scheduled from 11 a.m. to 3 p.m. Saturday. Les Roberts will sign his latest novel, “The Lake Effect,” and Bruse Alexander will discuss “Blind Trust,” his first historical mystery set in London. As a way of saying thank you to fans of the mystery genre, Marsha Landreth will present a numbered and signed short story, and Paul Bishop, the LAPD detective and novelist, has signed copies of his story “Ebenezer: A Hard-Boiled Christmas Carol,” which will be given to each guest at the party.

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Wesley Eure, who played Michael Horton on the TV soap, “Days of Our Lives,” will sign his new children’s book, “Red Wings of Christmas,” at 2 p.m. Saturday at Barnes & Noble in Ventura.

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Bah, Humbug! James Earl Jones and Martin Sheen will celebrate Charles Dickens in a production hosted by Robert MacNeil. Broadcast is at 1 p.m. and again at 7 p.m. Monday on KCRW-FM affiliates in Ventura (89.1), in Ojai (102.1) and in Santa Paula, Moorpark and Fillmore (102.3). The program will be rebroadcast at 6 p.m. on Christmas Day.

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The Christmas Wish Tree at the Camarillo Library, 3100 Ponderosa Drive, is installed and loaded with ornaments inscribed with the titles of books and audio cassettes the library would love to receive as gifts. Purchase one of the listed titles and your name will be affixed to a bookplate, and you may keep the ornament to hang on your own tree.

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Free-lance journalist Ann Shields of Ventura won first prize and a cash award for her short story, “A Pardon for Uncle Vito,” chosen from among hundreds of manuscripts submitted to the annual Dorothy Daniels writing competition, sponsored by the Simi Valley Pen Women.