who said don't judge a book by its cover

The exact phrase “Don’t judge a book by its cover” is a proverb with no single, universally agreed‑upon original speaker; it evolved over time rather than coming from one famous quote by a specific person. It was popularized in mid‑20th‑century English, especially in print and later in everyday speech.

Quick Scoop

Who said it first?

• The idea goes back at least to the 19th century, where similar wording appears in newspapers and literature warning people not to be misled by appearances.

• A very close form appears in a 1946 murder mystery novel, Murder in the Glass Room , with the line “You can never tell a book by its cover,” which helped cement the modern wording.

• Because it appears as a piece of advice and “old proverb” in different sources, it is treated as traditional folk wisdom rather than a line invented by a single, clearly credited author.

How the phrase evolved

• Earlier versions include expressions like “you can’t judge a book by its binding” and more general sayings about not trusting appearances, which gradually shifted toward the exact cover/book wording.

• Over time, the phrase became a common English idiom meaning you shouldn’t form an opinion about a person or thing based only on outward looks.

Why people still quote it

• Today it’s used in everyday conversation, classrooms, self‑help content, and online forums as a quick reminder to look beyond first impressions.

• It often shows up in discussions about prejudice, stereotypes, or stories where a character turns out to be very different from how they first appeared.

TL;DR:
No single famous person definitively coined “Don’t judge a book by its cover”; it grew out of older “don’t trust appearances” proverbs, with printed versions in the 1800s and a near‑modern form popularized by a 1946 novel.

Information gathered from public forums or data available on the internet and portrayed here.