Empire of the Sum by Keith Houston. Another entry from both the I-heard-about-it-on-a-podcast and Kurlansky-style-non-fiction categories, Houston's fast, funny, and thoroughly-well-documented book is subtitled The Rise and Reign of the Pocket Calculator and it lives up to its name. Starting with the axiom that the existence of a pocket calculator necessitates pockets and calculation, Houston takes us through the development of both, from biology and prehistory onward. Pockets are dispensed with pretty quickly, but the path to a calculator as we know it 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.