VALDOSTA — For more than 30 years, Susan McKey Thomas has strived to cull evidence of hard facts from the monolithic legend that is John Henry “Doc” Holliday.

But her research and investigation runs much deeper than mere historic interest and much longer than the past few decades.

Susan McKey Thomas of Valdosta is a second cousin of Doc Holliday. She is the granddaughter of William Harris McKey. Doc Holliday was the son of Alice Jane McKey Holliday. William Harris and Alice Jane were brother and sister.

Her research resulted in a 1973 book, “In Search of the Hollidays,” with the late Albert S. Pendleton Jr.

This book has been republished, and Thomas is scheduled to sign it this weekend as part of the Lowndes County Historical Society’s 16th Annual Jingle Bells Tree & Open House in the museum. The historical society has been referring to its event as the Jingle Bells Tree & Open House since the early 1990s.

In addition to the book signing, the event features a display on James Lord Pierpont, the composer of “Jingle Bells,” who lived in Valdosta during the 1800s. It also features an on-going exhibit of costumes from Valdosta’s past Mystery Balls.

But the book signing is the featured event.

“The reprint contains an addendum and photographs not available at the first printing,” notes Donald O. Davis of the Lowndes County Historical Society.

“Doc” Holliday, of course, is tied forever with the American West, Wyatt Earp, and the Shootout at the OK Corral, but he is also an intrinsic part of Valdosta’s history and lore. What follows is from a 2005 Valdosta Scene story on Susan McKey Thomas and “Doc” Holliday.

To the Valdosta McKeys of the early 20th century, “Doc” Holliday was something of an off-beat relative within the family. The type of relative whom families do not often mention amongst themselves let alone publicly. For decades, too, the McKeys had no reason to mention Doc because few remembered his tale.

The O.K. Corral story had fallen out of popular lore in the immediate decades after the event. In the 1930s, however, writer Stewart Lake published a book called “Wyatt Earp: Frontier Marshal.” Though a mix of mostly fabrication presented as fact, the book was a bestseller and revived the tale of the O.K. Corral, eventually leading to the first movie, “Frontier Marshal,” in 1939, more than 50 years after the shootout. Cesar Romero, who later played the Joker in the 1960s “Batman” TV series but was better known in the ’30s for playing exotic Latin lovers, was cast to play “Doc” Holliday opposite of Randolph Scott’s Wyatt Earp.

At first, when Stewart Lake wrote to Valdosta seeking relatives from Holliday’s early life, the McKey family was mildly surprised, with an attitude of “why would anyone want to know about that?” As more books followed and then with the coming of the 1939 movie, reaction from the family’s older generation bordered on shock and outrage.

Before the books and movies, Susan McKey Thomas cannot recall any member of her family ever talking about him, either as her cousin John Henry Holliday or by his more famous sobriquet “Doc” Holliday. But as a youth removed by generations from him, Susan McKey Thomas says it was fascinating to suddenly have this famous member of the family who was the subject of books and was being portrayed in movies. To her, it was exciting and an interesting dimension to the family tree. He was little more to her than an interesting conversation piece for the next few decades as the “Doc” Holliday legend grew. Susan McKey Thomas was busy during those years raising her family.

About 30 years ago, Thomas participated in a project of the Lowndes County Historical Society which had descendants of Valdosta’s early families researching their respective histories. She accepted an assignment to learn more specifically about the life of second cousin “Doc” Holliday.

It was a daunting challenge. Holliday had lived and died nearly a century earlier. His fame stemmed from an event that wasn’t mythologized until almost 50 years after his death, and that legend had then percolated and grew for almost another 40 years. Discerning fact from the legend would not come easily, but Thomas became more intrigued by her search the deeper she dug.

Thomas did discover evidence that filled in blanks in the real biography of “Doc” Holliday. She was able to confirm what dental school he attended in Pennsylvania, Pennsylvania College of Dental Surgery in Philadelphia, and found the date of his graduation, March 1, 1872.

Thomas’ discoveries and efforts led to “In Search of the Hollidays: The Story of Doc Holliday and McKey Families.”

As for Thomas, who remains a prolific historian of local lore through the Lowndes County Historical Society, she reached a saturation point in her “Doc” Holliday research where she no longer had a desire to pursue it further. Still, she is often contacted by authors, researchers and others about her famed second cousin, and Thomas is more than accommodating in discussing him and her work. Shortly after the release of the film “Tombstone” in the early 1990s, producers contacted Thomas and asked if she would participate in a documentary uniting the descendants of the O.K. Corral’s principal characters of the Earps, the Clantons and Holliday. Susan McKey Thomas wasn’t interested, but her son, Bud Thomas, agreed and participated in the documentary which aired on the Showtime cable TV channel.

Of the movie performances, she admits Val Kilmer’s portrayal of “Doc” in “Tombstone” is her favorite. Thomas could see “Doc” having a similar sense of humor. But she is most fond of actor Stacy Keach, who portrayed Holliday in the movie “Doc.” Thomas sent copies of her book to the living actors who had played Holliday, but only Keach wrote her back.

“You can tell the genuine people from the fakes in this world,” Thomas says of Keach, but it is a line that could apply to her research of “Doc” Holliday also. She spent years trying to find the genuine John Henry Holliday buried in the concoctions of “Doc.”