This liber amicorum honours Professor Jan Tissot van Patot as a scholar, referring in particular to his concern with transport economics. The signi ficance of his work grew out of his influence within Netherlands Railways as, with the passage of the years, he dedicated himself increasingly to the vastly wider field of transport economics. I would emphasize, however, that his theoretical knowledge and views in wider contexts have also been of great value to Netherlands Railways, and I greatly appreciate this opport unity of referring to this aspect in a few personal words. It is characteristic...