Best-selling author Harris has admirably gone all over the map in her career, from magical realism to historical fiction, but how would one describe A Narrow Door? On the one hand, it’s a psychological thriller. Rebecca Buckfast has recently been made headmistress of St. Oswald’s, a posh old boys school, where her rise as the first female to occupy the top position and the addition of female students - and the attendant name change from 'School For Boys' to 'Academy' - is ruffling a few feathers. Before any of this becomes apparent, this reader sat up straight when she laid out her stall by admitting to two murders as early as the preface.

Students approach Classics Master Roy Straitley after discovering a body. It should be noted here that is the third volume by Harris to feature Straitley and St. Oswald's - and it's not the first time Buckfast has appeared either - following on from Gentlemen & Players (2005) and Different Class (2016) but I've yet to read either of them and so can assure you that A Narrow Door works just fine as a stand-alone read. Straitley, who despite himself seems a decent enough sort of chap, is a remanent of the old St. Oswald's who can neither get his head round the term 'headmistress nor successfully negotiate the pronoun minefield around a trans pupil. He brings this news of another scandal - he's already haunted by his fallen friend, Eric Scoones - to the new boss. Prompted by this turn of events, Buckfast recounts her past to Straitley in a series of conversations. Chapters are told from the point of view of the 'white queen' or the 'black king', which should indicate how Rebecca manipulates the old don.

She had been a happy child until the disappearance of her brother Conrad when she was five years old, which naturally had a devastating effect on her family. Her parents never recovered and became easy targets to anyone who cruelly offered even a sliver of hope. Forced to confront this trauma by the school boys' discovery, Rebecca starts to piece together what actually happened to her brother and how she has been haunted by the mysterious and unnerving Mr Smallface, a presence that now appears to be in contact with her daughter, Emily. The more that is revealed, the more complicated it all becomes.

At the same time as all that, Harris lets the narrative illustrate the trials that women have to face to squeeze through the slender aperture of the title in a male dominated world like St. Oswald’s, with the new Headmistress determined to not let any man - whether it be her late brother, her partner Dominic or the curious Straitley - keep her from where she's going. Whichever way you read it, and you'll get special smug swot points for nodding at how the book is divided into eight parts that correspond to the rivers of the ancient Greek underworld and the lands that lie beyond them, which reflect what's going on - lamentation, woe, forgetfulness, etc., this is a compelling novel that’s difficult to put down.