The Rough Guide to Psychology was Christian’s first sole authored book, published to critical acclaim in 2011. Scientific American Mind called it ‘consistently lively’ and ‘accurate, up-to-date and easy to read’. The Psychologist magazine described the book as ‘disarmingly appealing to the deep desire to know ourselves’ and ‘frighteningly up-to-date’ and praised its tone of ‘wonder but also healthy scepticism’. Mind Hacks blog remarked ‘Wonderful breadth, impressive depth and fun throughout’. Circa 30,000 copies sold worldwide to date.