Elements of Lettering
The pattern
This still is filed under Specimen as proof.
Define
A specimen (type, material, finish) is shown so the product proves itself under comparison.
Mechanism
Controlled display. Same conditions, side by side, no adjective required. The sample is the sentence.
Verdict
Buyers choose by eye or by hand and we can put the real thing in front of them.
Why it works
The controlled variable is the sales mechanism. Every plate carries the same pangram at the same size, so nothing differs but the face, and the reader's eye is forced to notice the design instead of the words - the oldest and cleanest way to make a specimen persuasive. The prefatory note also does classic positioning work: it names the companion volume, states what this book deliberately is not, and defines the job narrowly - what letters are, not how to draw them - which lowers the promise to something the book can actually keep. Facing each plate with a short note on that alphabet's origin means the reader gets the argument and the artefact on one spread without either interrupting the other.
Steal this when
Steal the fixed-copy comparison whenever you are asking someone to choose between options that differ on one dimension - fonts, layouts, finishes, packages: hold the content identical across every sample so the choice cannot hide behind different words. The prefatory note is also a model for scoping a deliverable: say what it is not, before anyone can be disappointed.