The collection contains research materials relating to Baron Thomas Babington Macaulay. The majority consist of photocopies of letters by Macaulay spanning his lifetime. These may be photocopies of original letters, copies from microfilm, copies of published letters, transcriptions, or excerpts. Pinney's notecard index of Macaulay's correspondence reflects the majority of the chronologically sorted letters. There are also folders of unsorted letters and letters of indeterminate date. The series of correspondence by others consists of photocopies letters about Macaulay by family members and others, both during and after his lifetime. Other research materials include collected biographical materials, published articles about Macaulay, catalogue information about collections of Macaulay letters and notable people, copies of literary and business works by Macaulay, and copies or transcriptions of journals and memoirs about Macaulay by family members. Bound volumes include published works by Macaulay family members and a dissertation about Macaulay's literature. The index of letters is an index prepared by Pinney on notecards. It is organized by date. The completeness of this index has not been verified. The microfilm series consists of four reels of microfilm.