The records of Lanman & Kemp document the operations of the wholesale drug business in the years before the development of modern pharmaceuticals. They also show the importance of New York City as a center for the import, export and re-export business and of London bankers in financing international trade and extending credit.

The collection is very rich for students of business history. Domestically, Lanman & Kemp's correspondence with other United States firms in the 1850s-1870s demonstrates the wholesale trade in drugs and chemicals, especially in New York City; the relationship of New York firms with small-town retailers. In terms of foreign trade, the collection highlights trade connections between New York and the rest of the world. There is much material with which to study banking and credit history, as the archives contain letters both from large banking firms and from countless small businessmen requesting credit or authorizing bank draughts. Businessmen in South America sometimes paid their bills with local produce, especially hides and coffee. Drug retailers in South and Central America can be studied through the letters, which often contain ornate letterhead describing what the store sold, discussions by the writers of their business experiences, and detailed orders naming many of the items required to stock a pharmacy. The large number of letters can also shed light on the material culture of international business: stationery, especially decorative letterhead and mourning stationery, and the use of formal business language. Long, sustained runs of telegraphic correspondence, especially between Lanman & Kemp and bankers in London or merchants in the Middle East, demonstrate the growing importance of telegraphy in the mid-nineteenth century. Many of the telegrams are written in code. Most of the letters are dated by the sender and by Lanman & Kemp, indicating when it was received; this can be used to calculate the time required to send international letters by steamers during this period. There is also evidence of Lanman & Kemp's forays into advertising: records of advertisements in foreign newspapers, and a few trade cards and newspaper advertisements are included.

The nature of the Lanman & Kemp business indicates the collection's use for medical history. Thousands of different drugs are mentioned in orders, from simple herbals such as arnica to chemicals such as gold nitrate, as well as preparations such as litargirio and opodeldoc. Many correspondents also request specific medical equipment and tools, and supplies such as bandages, glassware, etc. These letters can give an idea of the medical preparations in demand in South America, and the nature of medical practice and pharmacology in large cities such as Havana as well as tiny towns in Mexico and Colombia. There are some records of orders from North American druggists as well, although generally the letters are not as detailed. Letters for New York State and Wisconsin are particularly rich. The domestic correspondence also suggests the intense activity in pharmaceutical merchandising in New York City and in trade with the United States hinterland.

Certain specific commodities can be studied with this collection. This collection contains much information on the manufacture, international trade, and sale of opium. Lanman & Kemp purchased opium, mostly in Turkey, and sold it around the world; it was one of the firm's most popular items. Lanman & Kemp were also heavily involved in "patent" or proprietary medicines: the firm sold its own trademarked preparations (Florida water, sarsaparilla, worm pills, chest medicine) along with those of other American and European companies. The firm bought raw materials (spices, extracts, gums and resins) in India, Southeast Asia, and France, either to use to manufacture its own preparations or simply to trade.

The Foreign correspondence series, two largest files are for the London banking firm of William Henry Cole (4,222 items) and the Smyrna opium merchant Alexander Sidi (1,231 items). The majority of the foreign correspondence consists of folders with fewer than twenty-five items. However, many of these folders contain detailed orders that shed light on the foreign drug business, and on the nature of drug retailing in South and Central America. Many of the orders contained in letters from South and Central America are very detailed for everything needed to stock a drugstore.

The Domestic correspondence series has thirty-four states and the District of Columbia represented within the correspondence, but the bulk is centered on New York City, the Mid Atlantic states, New England, and the Upper Midwest. Correspondence with firms in New York City is mainly receipts and invoices from other wholesalers and manufacturers. Correspondence with firms outside the city is usually orders from druggists in other cities and towns. Domestic correspondence is almost entirely in English, with a few Spanish- and French-language items.

The Internal files series includes shipping documents, checks and bills of exchange, company inventories, banking and account books, and miscellaneous items. Also included are correspondence of Rear Admiral Joseph Lanman, brother of David T. Lanman, and records of Edward Kemp's role as treasurer of the Episcopal Church of St. Peter's in Galilee in Monmouth Beach, New Jersey, which was located near his county estate at Rumson.

There are also two folders of photocopied reference material, left by previous researchers, that might be of interest to scholars of stamps, military history, or the California gold rush.