This handbook is a guide to ordinal number theory. Ordinal theory itself focuses on satoshis, giving them individual identities and allowing them to be tracked, transferred, and given meaning.

Satoshis, not Bitcoins, are the atomic, native currency of the Bitcoin network. A bitcoin can be subdivided into 100,000,000 satoshis, but no more.

Ordinal Theory does not require sidechains or tokens outside of Bitcoin and can be used without any changes to the Bitcoin network. It works now.

Ordinal number theory gives satoshis a numismatic value, allowing them to be collected and traded as curios.

A single satoshis can be inscribed with arbitrary content, creating unique bitcoin-native digital artifacts that can be kept in bitcoin wallets and transferred using bitcoin transactions. Inscription is as durable, immutable, secure and decentralized as Bitcoin itself.

Other more unusual use cases are possible: off-chain colored coins, public key infrastructure with key rotation, decentralized alternative to DNS. For now though, such use cases are speculative and exist only in the minds of fringe ordinal theorists.