"A Handbook of Useful Tables" Lloyd E. Smith, 1943 (No. 835 - Little Blue Book)
 
Acting as a versatile "cheat sheet" for daily life, this guide brings together a wide range of essential math and measurement data in one place. It covers everything from basic multiplication and interest calculations to more complex tasks like converting metric units or finding square roots. The book also includes a variety of specialized lists, such as common household measurements, medical symbols, and even the different sizes of printing type. By collecting all these facts into a simple, portable format, the handbook ensured that useful information—once tucked away in heavy textbooks—was easy for anyone to find and use on the go.