For a more narrative overview, I've also found "Spring Forward: The Annual Madness of Daylight Saving Time" by Michael Downing (2005, ISBN 1593760531) to be an entertaining and informative read. It doesn't skimp on details, but at the expense of some thoroughness and organization (from a data standpoint), it tells a good story of how we got into the whole mess in the first place. It also cites a large number of supporting references, so depending on the areas/years you're looking for, it could be helpful.