This thesis is a stylistic study of Mark Haddon’s "The Curious Incident of the Dog in the Night-Time" (2003). The aim of the thesis was to explore the mind style of the narrator of the novel, Christopher Boone, who suffers from Asperger’s Syndrome. In other words, we wanted to see how Christopher’s idiosyncratic cognitive habits and word view can be reflected in his consistent linguistic choices. In order to do this, both qualitative and quantitative methods were employed. The theoretical fundament was Halliday’s Systemic Functional Grammar, but pragmatic theories on discourse coherence were utilized as well. It is argued that Christopher’s idiosyncratic mind style can be reflected in patterns of cohesion, coherence and transitivity and that the consistency of these patterns can be proved by way of a quantitative key word analysis by means of the Wordsmith Tools concordancing package.