In the days before pocket calculators, the numbers that most professionals needed -- bankers, insurance agents, ship captains, engineers — were to be found in lookup books like this, filled with tables of figures.
In de dagen vóór de zakrekenmachines, vond je de getallen die de meeste professionals -- bankiers, verzekeringsagenten, scheepskapiteins, ingenieurs — nodig hadden terug in naslagwerken als deze, vol tafels met getallen.