Definition
A letter book is a bound volume maintained by a merchant, trader, or business entity containing copies of outgoing correspondence — letters sent to customers, suppliers, creditors, or other correspondents. Before the era of carbon copies, photocopiers, and digital records, the letter book was the standard method of preserving a sender's record of what had been written and to whom. Copies were typically made by pressing the original letter against dampened tissue paper (a "press copy") or by manual transcription into the volume.
In legal proceedings, letter books carried evidentiary significance as business records: they were treated as secondary evidence of the contents of correspondence, admissible upon proof that the original letter had been lost or upon notice to the opposing party to produce the original and failure to do so.
---
Common Language
Modern common usage (Wiktionary): A book in which copies of letters sent are kept; a bound record of correspondence.
Historical common usage (Webster's 1913): A book in which letters are copied as sent, or in which originals received are filed.
The common and legal meanings are closely aligned here. The legal significance of the term lies not in any departure from ordinary meaning but in its evidentiary treatment: courts had to determine whether press copies and transcribed copies in a letter book qualified as admissible secondary evidence, and under what conditions. The term is therefore more procedurally loaded in legal contexts than its plain meaning suggests.
---
Why It Matters in Research
Researchers working in commercial litigation records, probate files, or mercantile disputes from the eighteenth through early twentieth centuries will encounter letter books as a class of documentary evidence. Understanding the evidentiary status of letter book copies — secondary evidence, not primary — explains why courts frequently required a predicate showing (loss of the original or notice to produce) before admitting them.
Several research traps deserve attention:
First, the evidentiary rules governing letter book copies were not uniform across jurisdictions or time periods. Bouvier's flags this explicitly, noting that decisions were "not entirely uniform." A researcher reading a nineteenth-century opinion that admits or excludes a letter book entry should not assume the rule applied elsewhere.
Second, the press copy and the manually transcribed copy were treated as legally equivalent by most courts — both secondary — but this equivalence was itself contested. The physical process of press copying (ink transferred under pressure to tissue paper) produced a near-facsimile, which some courts viewed more favorably than a handwritten transcription made later. This distinction may appear in evidentiary arguments found in trial records.
Third, for corporate and partnership disputes, letter books often surface as the most complete surviving record of the business's communications. They appear in discovery disputes, will contests involving business interests, and fraud cases. Knowing that courts treated them as secondary evidence helps interpret why counsel often expended effort proving the loss or unavailability of original letters before introducing the book.
Fourth, the letter book as a record-keeping practice largely disappears from legal sources after the widespread adoption of carbon paper (late nineteenth century) and later photoduplication. Researchers in post-1920 materials will rarely encounter the term in its traditional sense.
---
Historical Dictionary Support
Both Rapalje & Lawrence and Bouvier's define the letter book consistently: a merchant's or trader's record of copies of sent correspondence. The definitions are substantively identical, reflecting a settled commercial practice rather than a contested legal concept.
Bouvier's adds the critical evidentiary layer that Rapalje & Lawrence omits: the specific holding that press copies in a letter book stand in the same evidentiary position as copies transcribed from the book — both secondary — and the acknowledgment that authority was split. Bouvier's references to Campbell's reports and Connecticut Reports point to real litigation in which the admissibility of letter book copies was argued and decided, confirming this was not a purely academic question.
What neither source addresses is the organizational or authentication dimension: courts also occasionally required evidence that the book was regularly kept in the ordinary course of business before admitting its contents — a precursor to modern business records doctrine. That framing does not appear in these dictionary entries but surfaces in the underlying case law.
The historical dictionaries do not address digital or electronic analogs because none existed, and no modern dictionary treatment of "letter book" exists in legal sources. The term is effectively historical.
---
Jurisdictional Note
Evidentiary treatment of letter book copies varied across American and English courts throughout the nineteenth century. English courts addressed the question earlier given the volume of commercial litigation in London, but American courts developed their own lines of authority. Researchers should treat any general statement about letter book admissibility as jurisdiction-specific until confirmed by local authority.
---
Encyclopedia Cross-Reference
No Law Mind Encyclopedia entry is a close match for this term in its primary commercial-records sense. Researchers investigating the broader evidentiary treatment of business records may find contextual background in related encyclopedia coverage.
---