Letters That Make Good: A Desk Book for Business Men
The pattern
This still is filed under Direct-from-the-founder letter.
Define
A letter in one person's voice, written as if to one reader, signed by the person who owns the outcome.
Mechanism
Personal authority. The signature is the proof. The tone is the brand. A committee cannot write this and keep the mechanism.
Verdict
Trust sits on a person
Why it works
The book separates principle from evidence and then lets the evidence carry the weight. Part I breaks a letter into eight named parts (plan, data, message, style, opening, body, closing, mechanics) so the reader gets a checklist instead of a theory, and each part is signed by a practitioner, which buys authority the editors did not own alone. Part II runs on one elicitation prompt, "The Best Letter I ever Used and Why", which forces every contributor to hand over the asset and the result together and converts a swipe file into a set of cases. Reproducing the letters photographically rather than resetting them teaches the physical mechanics too, since the letterhead, the typeface key line and the ribbon impression are half of what made the letter land.
Steal this when
Copy this when you want to build authority in a craft you do not personally own: commission short signed chapters from recognised practitioners, then carry the real weight with a large annotated evidence section where every example states what it produced. The "best X I ever used and why" prompt is the engine, because it makes contributors surrender both the artefact and the number attached to it.