If this blurb were a movie title it would go like this: Threshold, or, how I learned to stop worrying (about what sort of novel this is) and love the narrator, whose brilliance and humour on drugs and literature, sex and boredom and death, leave me in awe

RACHEL KUSHNER

Not only the best work to date from a writer who gets better and better with each release, but also a unique, engrossing and strangely thrilling way to shake this new year into existence and make it tingle with promise

IRISH INDEPENDENT

This sly tale told against its author takes the reader on a destabilising voyage of discovery and self-disgust … Each section of the book – cleverly masked as a tale told against its teller – blossoms critically in two or three directions … Whatever else it is, Threshold is surely the record of a voyage – a book of experience in some quite old-fashioned, powerful sense

GUARDIAN

Not many books manage to expand your mind, do your head in and set you laughing out loud. This one does, and Doyle's words sing on the page

SPECTATOR

A book that casually vaporises the boundaries between autobiography, travelogue and philosophical/pharmacological exploration … If you fancy some Terence McKenna adventures in consciousness expansion, or Isherwood-esque exile in the most decadent cellars of Berlin, or down and out sojourns in Paris and London, step right up

IRISH TIMES

Dead-pan satire – a cautionary tale of dissipation and drift; a masterclass in what not to do

NEW STATESMAN