This ledger covers the period February 1880-January 1881. It contains accounts payable and receivable, along with records of cost accounts, royalty accounts, and labor costs. The majority of the entries appear to have been used to allocate costs (identified by voucher number) to Edison companies, experiments, and product lines. Some accounts are merely transitional continuations of accounts from the "old ledger" (#3) to the "new ledger" (#5). A profit-and-loss account for 1880-1881 appears on page 401. It is continued in ledger #5 (page 503). The spine is labeled "General Ledger March 1880 to December 1880" and "Ledger 4." The book contains 693 numbered pages and an index. Approximately half the pages are blank.

Missing page numbers: 417-428.