According to the Institute for Heraldic and Genealogical Studies, which Ancestry cites as their source, this is an index to more than 10,000 original marriage licenses of over a dozen major London parishes. These include "St Martin in the Fields 1765-1837; St Mary Putney 1822-1837; Holy Trinity Chelsea 1832-1837; St Leonard Shoreditch 1774-1837; St Dunstan in the West 1731-1837; St Paul Deptford 1779-1833; Christ Church Spitalfields 1757-1780; St John Hackney 1779-1837; St Paul Covent Garden 1734-1837; Kensington, Deptford, Whitechapel (some) etc. 1707-1837."
The collection is name indexed. There is also a browse file by year. Missing years are 1716, 1717, 1753, 1755. The last year is 1892 after which there is a collection of 105 poor quality pages, many torn, categorized as "Not Stated." From 1713 to 1733 the entries are handwritten in Latin with the early years difficult to read. Thereafter the language is English with a printed form used from 1759.
Perhaps like me you're curious about Crisp whose name is in the collection title.
Genealogy Hub has a list of publications of Frederick Arthur Crisp, 1851-1922, with surname lists of contents and links to several of his texts in the Internet Archive. Crisp became wealthy in the patent medicine business in London. When he died his estate was nearly 164 thousand pounds.
An interesting coincidence is that Butler and Crisp, wholesale medicine company, had offices at Charterhouse Buildings which now houses the Society of Genealogists.