I just finished reading "Spring Forward", a history of Daylight Saving time written by Michael Downing. It's a short, funny book - I never realized how much confusion surrounded this whole topic. Never mind the recent change here in the US and Canada - this book traces the long century of confusion surrounding the idea, and how - before the 1970s - the adoption of daylight saving time varied all across the country. Worse, before the 1880s and railroad time, time keeping varied across the country, period. It's a fascinating little book, and a very entertaining read.