ArjanCodes (5 mentions) emphasizes `functools`' role in preserving function metadata, especially when using decorators, as highlighted in videos like "The Hidden Dangers of Python Decorators" and its general importance alongside modules like threading, as seen in "The Lazy Loading Pattern: How to Make Python Programs Feel Instant."

functools is a Python standard library module for higher-order functions. It supports functional programming through caching, partial application, and decorator creation. Its key features include `lru_cache` for memoization, `partial` for fixed arguments, and `wraps` for metadata preservation. `functools` reduces boilerplate in comparisons and orderings, improving code efficiency.