Shiela Crerar, the charming psychic investigator who was the creation of the virtually untraceable author Ella Scrymsour, appeared in a series of six stories in The Blue Magazine between May and October 1920.

An orphan, Crerar was forced into her unlikely career following the death of her guardian uncle; and, on moving to London, soon began to realise her special gifts. Whether or not similar circumstances and surroundings reflect events in Ella Scrymsour's own life can only be a matter for speculation, but the six tales of the young psychic investigator which flowed from her pen are well crafted and wholly delightful.

Of all the investigators in the Ash-Tree Press Occult Detectives Library, Shiela Crerar is probably the most obscure, the consequence, notes editor Jack Adrian, of the stories being published in the short-lived, low-budget Blue Magazine, which eventually floundered in the late 1920s.

Throughout the series, Shiela Crerar is loved and admired by Stavordale Hartland, the nephew of Lady Kildrummie, to whose aid Shiela is called in the opening story, 'The Eyes of Doom'. Hartland is often in Shiela's thoughts, and is occasionally summoned to assist in her investigations; but although Hartland has marriage in mind, Shiela firmly tells him, 'I have set myself a task, and I must complete it.'

Whether she does, in fact, complete it, and whether Hartland is successful in his quest, will be revealed to the reader by the end of the final story, 'The Wraith of Fergus McGinty'. Before that, however, Shiela tackles such cases as 'The Death Vapour', 'The Room of Fear', 'The Phantom Isle', and 'The Werewolf of Rannoch', and establishes herself as one of the psychic detectives about whom one wishes more had been written.