A ‘Bradshaw’ is a complete timetable for all the railways in the British Isles; with it the reader can plan long, complicated train journeys. Suppose, for example, one wished to travel the 94 miles from Lampeter to Hay on Wye – an awkward journey by rail – against the grain of the country. Bradshaw reveals that it would take 6 hours, with changes at Carmarthen, Llandeilo, Builth Road and Three Cocks Junction, which contrasts unfavourably with the hour or two a modern car on modern roads would need for the same journey. The Bradshaw used to plan this journey is not a current one; it was published in 1938. It is no longer possible to travel to Lampeter or Hay by train; the lines were all closed in the 1960s. Nevertheless, the 1938 Bradshaw is a collector's item, worth at least £20.

Why – the unenlightened generally ask – would anyone pay good money for an out-of-date railway timetable? A learning theory account might say that collecting timetables is a habit, hence that it was learned; reading Bradshaw and planning long journeys from A to B is reinforcing – but why? A trait account will subsume the habit under a trait, or traits, such as collecting old books and/or an interest in railways, but again fails to answer – or even ask – the question: why? A factorial account could offer only the broadest of explanations, a detail of a facet of a factor, or perhaps the conjunction of two such; it's the sort of thing someone with high scores on the orderliness facet of conscientiousness and the obsessionality facet of neuroticism might do. One theory of personality specialises in saying why people do things, and just happens to give a very specific answer to this particular question. The Man who Collects Bradshaws is driven by ancient forces hidden deep in his personality. The urge to possess copies of Bradshaw, and in particularly severe cases to complete the entire set, is the expression of long repressed childhood urges to do something much more basic.