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.
在没有电子计算器的年代， 很多行业需要用到数据—— 银行家、保险代理人、船长、工程师—— 都只能通过这样的大部头书中查找， 书里面是预先计算好的各种数字表格。