The Crowner John Mysteries are a series of novels by Bernard Knight following the fictional life of Sir John de Wolfe, a former Crusading knight appointed to the office of Keeper of the Pleas of the King's Crown (custos placitorum coronas), i.e. the King's Crowner or Coroner, for the county of Devon.

Crowners were appointed in 1194, during the reign of Richard the Lionheart, in every county to check on the corruption of sheriffs, but also to raise as much money as possible towards the payment of the loans that covered the huge ransom after the king's capture in Austria on his return from the Third Crusade.

As Crowner, Sir John has to investigate all sudden deaths, murders, rapes, assaults, fires, wrecks and catches of royal fish, as well as trying to drive as much custom (through fines and taking of property owned by convicted criminals) as possible into the royal treasury, instead of the old manor and shire courts. We learn that Sir John has a large area to administer – there are supposed to be three crowners for Devon but he is the only one. In all this, he is assisted by Gwyn, his old Cornish retainer and Thomas de Peyne, an unfrocked priest, who is his clerk. John's surly social-climbing wife Matilda is the sister of the sheriff of Exeter, Sir Richard de Revelle, who does all he can to make life difficult for John, who seeks solace in the arms of his Welsh mistress Nesta, the landlady of the Bush Inn in the city.

In Crowner Royal, set in 1196, John is appointed the first Coroner of the Verge by the king. He returns to Exeter in late 1196 in the next novel, A Plague of Heretics.

Apart from John, most of the main characters actually existed in history and every care is taken with research and the creation of atmosphere to offer an authentic picture of twelfth-century England. Most of the places described in the stories can be visited by readers today, even the gatehouse of Rougemont Castle in Exeter, where John had his office.