I just finished reading an advance copy of Eric Pallant's Sourdough Culture, which is coming out in a couple of weeks.
There are a few different threads to the book. One thread is an attempt to trace the lineage of the Cripple Creek starter he was gifted and which sparked his emthusiasm for sourdough. The other works forward in time from the earliest known evidence of breadmaking in Egypt, through the Roman Empire into Europe, and eventually from Europe to North America. It includes quite a bit of recent research including information on the industrialization of breadmaking and the move from sourdough to commercial yeast, something Professor Pallant won a Fulbright scholarship to study.
The last history of bread I recall reading was 6000 Years of Bread, which was originally published during World War II. A lot of research has been done since then. Professor Pallant's book brings that history up-to-date with recent scholarship and science to provide a much more complete picture of the evolution of bread. If that sounds like your kind of thing, check it out!