A Function Selector is an essential aspect of smart contracts, particularly those on Ethereum and other blockchains that support the Ethereum Virtual Machine (EVM). It acts as an identifier for specific functions within a smart contract.When a user wants to interact with a smart contract, they send a transaction that includes the desired function and its parameters. The Function Selector is the first four bytes of the Keccak-256 hash of the function’s signature, which consists of the function name and its input types. This selector allows the Ethereum network to determine which function to execute.For example, if a smart contract has a function named “transfer” that accepts two parameters — an address and an amount — the selector derived from this function’s signature will uniquely identify it. By using these selectors, smart contracts can efficiently route calls and manage complex operations, ensuring proper execution of transactions according to user intentions.