They form by far the largest collection of manuscripts at the library, and comprise all the manuscripts acquired by gift, purchase or bequest since 1756 that are not part of the "closed" collections or other named "open" collections.
Manuscripts in this collection have been used extensively as references in later works.
In the nineteenth century, British scholars (e.g., in the Dictionary of National Biography) assumed that the collection was so well known that a reference to "Addit.
Some subsets of the "Additional" series have been indexed separately.
This British Library-related article is a stub.