The path to a calculator takes us from counting rods to abacuses to slide rules and through mechanical and electrical adding machines to get to the glory days of the late 20th century and the ubiquitous TI-81. Houston rides us into the sunset as well, detailing the calculators replacement by - and assimilation into - the computer and mobile device. A great read all the way through, and I will be looking for his works on Punctuation and The Book.