Guildhall Library Manuscripts Section has closed permanently and merged with London Metropolitan Archives.

Details of arrangements for access to former Guildhall Manuscripts collections can be found here.
News of a programme to digitise genealogical sources at Guildhall Library and London Metropolitan Archives

Guildhall Library Manuscripts Section's online catalogue

News
Leaflet Guides to records

Electronic newsletter
Black and Asian people in records held by Guildhall Library Manuscripts Section

General Guide to Collections - this is currently being updated section by section (last updated 11th November 2009)
Business Records at Guildhall Library (last updated 15th October 2008)

City of London Parish Records

Livery Company Membership Guide
Indexes to Lloyd’s Captains registers
Indexes to Probate Inventories
Indexes to St Katharine by the Tower marriage licence records  
Indexes to parish returns towards rebuilding of St Paul’s Cathedral, ca. 1678

Details of newly catalogued collections
Publications available from Guildhall Library Bookshop

Policy documentation is available on the London Metropolitan Archives website.

Useful links:

London Metropolitan Archives