Thank you for the nice review of Curious Currency: The Story of Money from the Stone Age to the Internet Age. Regarding your comment that "the subtitle greatly oversells the scope of the book," I fear that you did not actually read the book, but merely thumbed through it. In fact, the first chapter (not illustrated) defines what money is, chapters two through five show the evolution of money from flint to coins, and chapter six covers money substitutes (including paper money) and our modern fiat money.
(I'm surprised in a way that you did not compare my: "Modern money is thus far less substantial than the money of our ancestors. Like the Holy of Holies--when you draw back the curtain, there is nothing there, just the "full faith and credit" of the issuing country." to last week's item from The Onion: "The U.S. economy ceased to function this week after unexpected existential remarks by Federal Reserve chairman Ben Bernanke shocked Americans into realizing that money is, in fact, just a meaningless and intangible social construct.")
Yes, on coins the emphasis is on "curious" ones, not the familiar machine-made round ones, and the same could be said for paper money. But the beginnings of coins and paper money are certainly included; the earliest Lydian electrum coin is illustrated (p. 101), as is the first banknote (p. 108).
As to "why another guide book to Odd and Curious currency is needed," this book is organized in a way that no other book on the subject ever has been (to the best of my knowledge). Quiggin is arranged geographically; Einzig is also arranged geographically (though with a separate historical section), and Opitz is simply an alphabetical encyclopedia.
Curious Currency shows the development of money from items of pure utility through those of increasing abstraction, up to our fiat money of today. (You have to read between the lines, though, to decide whether using pieces of printed paper for money is more "curious" than using shell beads or iron bars.)
When I started this project I knew that I had to square things with Chuck Opitz, since we needed to use his collection for most of the illustrations. He came on board willingly and caught a couple of mistakes in the text. His book, An Ethnographic Study of Primitive Money is by no means out of print, by the way, and he sells them on eBay from time to time.
In the news this week is yet another unusual money proposal. See the item below about the Pentagon shooter.
On another topic, Bruce Smith is correct that the exchange rate of 40 Quattrini = 1 Paulo is unsupported. It does not agree with the values in Hazlitt's The Coinage of the European Continent or Craig's Coins of the World 1750-1850, and the difference is not due only to the phonetic spellings of the denominations.
Hazlitt (Supplement, p. 115) gives 1 Paolo usually = 8 Baiocchi. Craig has 5 Quattrini = 1 Baiocco, 30 Baiocchi = 3 Paoli (or 3 Giulio). However, if 1 Paolo = 8 Baiocchi and 1 Baiocco = 5 Quattrini, then of course 1 Paolo = 40 Quattrini. Or if "Quattrino" means 1/4 Baiocco--as would be expected--and Craig's rate of 3 Paoli = 30 Baiocchi is correct for this period, then 1 Paolo = 10 Baiocchi = 40 Quattrini.
Or there could be a misprint in the chart.
The Giulio (Julio, Jule) is "apparently so-called from the Pope Julius II," per Hazlitt (p. 203); the Paolo was introduced by Pope Paul III, 1534-59. The Ponti is not mentioned by either Hazlitt or Craig and seems to be an obsolete coin of Malta.