The Book has 230 pages       The Book is 6 inches wide by 9 inches tall

Finally after 20 years of research and thousands of ECG's performed on racehorses, broodmares, stallions and foals Marianna Haun solved the mystery of Secretariat's large heart. There will never be another like Secretariat, yet Haun explains how breeders and handicappers can learn to identify the same physical characteristics exhibited by Secretariat on the race track and in the breeding shed.

Marianna Haun has spent the past 20 years trying to understand and solve the mystery behind the enormous heart found in Secretariat at autopsy. Haun, A Turf writer and reporter, published two previous books based on the sex-linked inherited X chromosome. In her research she has worked as a bloodstock agent, farm manager and pedigree consultant. 

While solving the mystery of Secretariat's enormous heart, Haun successfully duplicated large hearts while coordinating matings for Jim Spry, owner of Heartlines Ranch. Spry and Haun duplicated some 200 designer hearts earning Spry leading owner titles at Retama Park, Texas.

Haun and Spry successfully bred specific heart sizes based on pedigree analysis and physical traits identified in each mating. Not only did they breed a specific heart size, Haun was able to correctly identify both expressed and recessive X chromosomes received by each individual.

As a result of her work, Haun discovered a skeletal structure identifying the sex-linked X chromosome dating back to the Darley Arabian. Haun reveals in her book how breeders can use this technique, increasing their chances on the race track, and later in the breeding shed. The Darley Arabian is the source of Secretariat's large heart and enormous stride. Serious breeders looking for that extra edge in racing or performance should have this book in their library. Handicappers searching for large-heart long shots should know how to identify the industry labeled "freak" and capitalize on them before they become the odds-on favorite.

"The X Factor has turned the pedigree page upside down. It also sheds light on the previously inexplicable performance in the breeding shed of some of history's champions"...Penny Chenery, Owner/Breeder of Secretariat