A fascinating study of how history from sparse sources is developed. The Bactrian kingdom in Afghanistan consisted of Greeks left over from the Alexander conquest. When the book starts in the 1500-1700's, all that was known of them was from secondary sources - kings that were mentioned in surrounding areas sources. So a list of kings, not complete, and in shaky order.
But then people were finding coins, mostly with one particular king's name. Then by comparing more coins with similar characteristics, matches could be made on the king list. Wild guesses could be made on the relationships between the kings (sons, husband of other king's daughters, etc.) Looking at the craftsmanship (or lack thereof) other suppositions could be made on the state of the kingdom. Finally in the early 20th century, a candidate city was found that could have been Bactrian - really the only one. That is what is fascinating about the story - how the cities just disappeared from the Afghanistan land.
Along the way Holt teaches us how history is made from guesses that sometimes are as crickety as a house of cards when the facts are so few and debatable. Schools of thought on how to interpret and write the history come and go. Should we try to fit everything into a grand narrative that satisfies the human need for a story? Should we stop trying to concentrate on kings but rather try to find out how real Bactrian's lived through the evidence given us from the coins. This evidence could be as simple as the number of monograms (which might be places of minting) indicating the breadth of a kingdom, or as complicated as looking at individual coin die marks to see how accurate they are to see the quality of a society.
I didn't mind the coin focus of the history when it became apparent that this was what the history of Bactria is founded on. I think it also served as Holt's MacGuffin to dig deep into how history is really written and how no school of history is without real problems.