The number of books needed to be considered a library varies widely and depends on the context and purpose. There is no strict or official number. Common perspectives include:

• Starting a library can begin with as few as 50 to 100 books, especially for a small or personal library. The collection grows over time through donations or acquisitions.

• Some public perspectives suggest a minimum of 500 to 1000 books to feel like a library, with 500 books often cited as enough for a room to "feel" like a library.

• The American Library Association (ALA) mentions 5000 books as a number to qualify for a public or professional library, though this is often considered a benchmark rather than a strict requirement.

• For a small school library aimed at literacy, 15-20 books per child or a total around 2000 books for about 100 students is recommended to have a functional library.

In summary, a collection of as few as 50-100 books is enough to start a personal or small library, while more formal or public libraries often start from several hundred to thousands of books. The essence of a library is as much about curation, purpose, and accessibility as the number of books.