In unpacking credit relationships and payments over the past 1000 years in addition to how technological innovations are shifting the credit relationships/payments landscape from barter, commodity money, single layered to dual-layered financial money systems and from CBDC to stablecoins, this book systematically explores the various techniques that have been introduced in an attempt to improve the organisation, efficiency and stability of the IOU economy as a way to mitigate or prevent the universal challenge of the IOU economy from binding.