Elizabeth Lamb (bap 1751, d 1818) was married to Peniston Lamb, 1st Viscount Melbourne and was commonly known as Lady Melbourne. She was a Whig society hostess and was influential in the lives of many powerful men of the age, including the future George IV. Her friendship with Lord Byron began in 1812 and she helped him end his affair with her daughter-in-law, Lady Caroline Lamb. When Byron separated from his wife, Lady Melbourne remained loyal to the poet, despite his wife being her own niece. Their close relationship continued until Lady Melbourne died in 1818.

Lady Melbourne and Byron exchanged hundreds of letters, full of personal detail and information about wider regency society. Byron often confided in Lamb about his relationships and after the death of Lady Melbourne, Byron tried to regain his letters in order to prevent others from using the personal content against him. This series contains over 150 letters of Byron to Lady Melbourne as well as her letters to the poet. In addition, there are letters of Lady Melbourne to John Cam Hobhouse, another intimate friend of Lord Byron.

There are also copies of correspondence between Lady Melbourne and Lord Byron within this sequence.