Anyone interested in the more modern origins of fiat might start here: https://imprimis.hillsdale.edu/inflation-united-states/
However, author John Steele Gordon forgot to include an interesting tidbit about the "greenback". Up to that point the reverse of the bill had a bond re-payment schedule. A $10 note, for example, would be worth $10.30, $10.60, etc depending on how long the bill (technically a short term bond) was held and not redeemed. Enter the "greenback" where there was no repayment schedule, the reverse was completely blank except for the green ink.