Imogen Duffy is a young Irish jump jockey whose star is on the rise. Her boyfriend, Liam Carson, is also a jockey, and unfortunately, he feels undermined by her success. He starts bullying Imogen and isolating her from family and friends. DARK HORSE is a book of two halves, the first narrated by Imogen, the second a more traditional crime story.   Imogen breaks up with Liam, but he doesn’t take it well, and his father, the racehorse trainer, fires the girl. Luckily, she has just won a fine race at the Cheltenham Festival in England. This puts Imogen on the radar of English trainers, and she gets a good offer out of the blue. Away she goes to England, but Liam arrives at Newmarket too, gets a job with another trainer, and starts stalking Imogen.   The novel does an excellent job of portraying the hassle, stress and nastiness of the situation. A woman being stalked by an ex-boyfriend feels betrayed and torn because she used to have feelings for him. The danger is real and the police seem unmoved by reports of a domestic incident.   Sid Halley, the former champion steeplechase jockey and former private investigator, is relaxing in well-deserved retirement with his wife Marina and their daughter Saskia. He narrates the second half, which explains a sparse police investigation and court proceedings. If you have previously met Sid, he’s unchanged except less keen to be physically attacked, and if you haven’t, he tells you all you need to know.   I particularly enjoyed the accounts of steeplechases, which include racing over the Grand National course at Aintree, cheering crowds at Cheltenham, and smaller, friendlier settings at local racecourses. Imogen’s career is clearly based on Rachael Black, a top Irish jump jockey who recently retired, having set a string of firsts for women in the sport. Imogen’s relative lack of experience is clearly stated. Ireland has about fifty regular jockeys, so in England, she became a small fish in a big pond. The sheer extra number of rides and racecourses provides the reason why so many Irish lads and lasses travel for work with horses. We also see the thoughtlessness of a male trainer whose young female staff are not chaperoned on tour, which would not require much effort. Actually, nobody comes out of DARK HORSE covered in glory. Felix Francis, son of the late steeplechaser and crime author Dick Francis, has skillfully picked out the loose threads in every area and tugged them hard. I consider this the best of his novels.