Business Correspondence Library, Vol. II: How to Get and Hold Business by Letter
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 subtitle acts as a strong benefit-driven headline, specifying exactly what the reader will learn (getting and holding business) and quantifying the contents.
Steal this when
When creating a volume in a reference series, ensuring each volume stands alone with a strong, specific promise.