Solidity libraries are collections of reusable functions that serve as smart contract modules for multiple contracts.
There are two types of libraries in Solidity: internal and external, differing in integration into bytecode and runtime invocation.
Internal libraries are embedded directly into the bytecode of the contract using them, while external libraries are standalone contracts deployed on the blockchain with their own address.
Understanding the differences and nuances between internal and external libraries in Solidity is crucial for making informed architectural decisions when developing smart contracts.