"That's Henry Cecil… he should have retired years ago." The words of a young trainer drifting across the Heath at Newmarket must have stung, but during Cecil's dog days in the Noughties it was not an isolated view.

For mighty indeed had been the fall: having taken over in 1969 from his stepfather, Sir Cecil Boyd-Rochfort, the Queen's trainer, by 1987 Cecil was champion trainer for the seventh time after producing 180 winners, the tally including a Derby, St Leger and seven Royal Ascot successes; in contrast, 2005 brought only 12 winners, none very prestigious. He was suffering from cancer, had financial problems and his two marriages had failed. But while his health is still fragile, the past few seasons have seen an unlikely renaissance, culminating in the feats of the wonder horse Frankel.

In Brough Scott he has found the perfect biographer, who knows everyone worth knowing in the racing world and can also write. Scott's definitive account of this shy, complicated dandy with an instinctive genius for training is at heart sympathetic, though he does not skate over his subject's flaws. Yet even Scott struggles to explain the almost mystical affection Cecil inspires in the public; when he won his first Classic for seven years, the 2007 Oaks, the crowd burst into a spontaneous "Three cheers for Henry Cecil!".

Scott deserves the same accolade for producing a classic book about a Classic legend.

Published in hardback by Racing Post, £20