It's possible to walk any of the many routes of the Camino Santiago by following a simple sign. Siempre sigue las flechas amarillas - always follow the yellow arrows. They're there wherever and whenever you need them: painted unobtrusively on the back of a street sign or on a rock or gutter; emblazoned on the side of a building; handwritten by a member of the local Camino Committee, or expensively produced by the provincial junta. By following the yellow arrows it's possible to walk the breadth (and, indeed, the length) of Spain without GPS or map or guidebook. Over the course of the Camino they came to symbolise for me, the presence of the Holy Spirit: usually unseen unless you pause and take the time to look; always there when you need them most; a faithful guide in unexpected places leading inexorably to the holy destination. They are like the myriad little promptings and leadings and coincidences and "chance" encounters, which anyone on a Christian pat...