Nobody has ever established who wrote this. Quote Investigator ↗ follows it through American newspaper columns for thirty years before Groucho’s name appears, and the early versions are not even about a dog: the first instance QI has found, in The Chicago Daily News of 6 July 1943, is credited to a Chicago Board of Trade press officer named Francis Bisson and runs “Outside of a horse, man’s best friend is a book, but inside a horse it’s too dark to read.” QI’s verdict on the Marx attribution is that the evidence for it “is very weak”.
“Outside of a dog, a book is man's best friend. Inside of a dog, it's too dark to read” Not Groucho Marx. An anonymous newspaper joke in print by 1943, originally about a horse; the Marx credit dates only to 1973. Via quotle.info
⚠ The slide-ready mistake: crediting this to Groucho Marx. Use the credit shown above instead.
Can you use it?
? We couldn’t verify where this wording comes from, so there’s no rights status to give. Safe to present as an unverified or anonymous line — just don’t assert a specific author or source.
Image direction — grounded in this quote’s real context; paste into your image tool
In context
Evoking the themes of knowledge and friendship. Theme: "Outside of a dog, a book is man's best friend. Inside of a dog, it's too dark to read". Atmospheric and restrained, cinematic directional light, a muted period-appropriate palette, fine grain and texture. Compose with generous empty space for the quote and a small credit line. No lettering in the image itself.
Minimalist
Minimalist editorial slide for the quote "Outside of a dog, a book is man's best friend. Inside of a dog, it's too dark to read". Clean background, a single muted accent color, generous negative space, subtle paper or linen texture, no literal illustration — let the words carry it. Reserve clear space for a serif quote and a small credit line. No lettering in the image itself.
Provenance
Where it actually comes from
Popular credit
Groucho Marx — listed under Misattributed on Wikiquote
Actual origin
American newspaper humour columns; no author ever identified
Earliest instance found by QI
The Chicago Daily News, 6 July 1943 — a horse, credited to Francis Bisson
Earliest with a dog
Binghamton Press, 2 December 1948 — but with “policeman” in place of “book”
Earliest with a dog and a book
The Nashville Tennessean, 23 November 1952 — credited to the comic Jimmy Husson
Earliest Groucho credit
Philadelphia Daily News, 5 April 1973 — per Quote Investigator
Outside of a horse, man’s best friend is a book, but inside a horse it’s too dark to read.
This is the earliest form Quote Investigator has located, from July 1943, and the animal is a horse. The switch to a dog is what makes the modern version work — it lets the first clause borrow the existing proverb about man’s best friend, so the joke sets its own trap. That refinement happened somewhere in a decade of anonymous newspaper reprinting, and no one knows who made it.
Quote Investigator’s article on the line ↗ lays out the chronology from primary newspaper citations. July 1943, The Chicago Daily News: the horse version credited to Francis Bisson. May 1947, the Nashville Banner: the horse version again, this time credited to the jockey Ted Atkinson ↗ — “probably because he is well-read and articulate”.
QI then tracks the joke mutating through columnists who were plainly just reworking a template. The dog arrives in December 1948, in the Binghamton Press — but with “policeman” swapped in for “book” — and a September 1950 instance opens the same way with “diamond”. The combination that makes the modern joke, a dog and a book and “too dark to read”, appears by November 1952 in The Nashville Tennessean, credited to a comic named Jimmy Husson. In February 1954 a form very close to the modern one ran in Boys’ Life’s reader-submitted joke column under the name of a boy in Cleveland.
The Groucho attribution arrives last. Per QI the earliest is a gossip column in the Philadelphia Daily News of 5 April 1973 — thirty years after the first citation, and in slightly different words: “Outside of a dog, a book is man’s best friend. That’s because inside a dog it’s too dark to read.” QI’s conclusion is that this “was a very late date” and the evidence for Marx “is very weak”.
Wikiquote ↗ files the line under Misattributed for Groucho and cites QI’s research for the same finding. Note that Wikiquote’s summary still names the May 1947 Ted Atkinson column as the first appearance; QI added the earlier July 1943 citation in an update dated 11 July 2026, which is the date used here.
No copyright status is asserted, and none can honestly be. The wording has no identified author and no established first publication — it surfaces in a 1943 newspaper column already in circulation and is reworked by a dozen anonymous hands over the following decade. The individual newspapers and magazines that printed each variant are separate copyrighted works, cited here as evidence of the joke’s travels rather than as its origin.
Rights status is our research, not legal advice — and copyright varies by country and edition. For commercial or published use, confirm with the rightsholder. See terms.
Fact-check
Often misattributed
A library-poster favourite that six different people have been credited with, none of them convincingly.
✕
Credited as the authorGroucho Marx Very late credit
Quote Investigator ↗ finds the earliest Groucho attribution in a Philadelphia Daily News gossip column of 5 April 1973 — thirty years after the joke’s first documented appearance, and in different words. QI’s verdict: “the evidence supporting an ascription to Groucho is very weak.”
~
The earliest name attachedFrancis Bisson Early credit
QI’s first citation, The Chicago Daily News of 6 July 1943, credits a horse version to Bisson, a public relations officer for the Chicago Board of Trade. Being the first name in print is not the same as being the author, and a column crediting a PR man with a gag is weak evidence either way.
~
The best-known early creditTed Atkinson Early credit
Two 1947 columns pin the horse version on the jockey Ted Atkinson ↗, one of them explaining the choice as being “probably because he is well-read and articulate” — which is a columnist reasoning about who ought to have said it, not reporting that he did.
~
Everyone elseJimmy Husson, Jim Brewer, Agro B. Arlo Early credit
QI records the joke credited to a nightclub comic in 1952, submitted by a boy in Cleveland to Boys’ Life in 1954, and attributed to an acquaintance of a sports columnist in 1975. A line that collects this many owners has none.
✓The joke was circulating in American newspapers by July 1943 ↗, about a horse, and no one has ever established who made it up. Groucho’s name was attached in 1973, last of at least six.
Context
Why it mattered
The joke’s evolution is easier to see than its author. The 1943 version is about a horse, which is nearly funny: the second clause lands, but the first has to explain itself. Swap in a dog and the sentence hijacks a proverb everyone already knows — man’s best friend — so the setup does no visible work and the punchline arrives from nowhere.
That improvement took about a decade of anonymous reprinting to arrive, and it is why the line is now on a thousand library walls. It also explains the drift to Groucho: by 1973 the joke sounded like a Groucho joke, because a decade of columnists had sanded it into one.
It took ten years and a dozen anonymous columnists to turn a horse into a dog.
Read the full story
One caution about sources, since this page cites two. Wikiquote’s summary of the line still names the May 1947 Ted Atkinson column as its first appearance, because Quote Investigator only added the earlier July 1943 Chicago Daily News citation in an update dated 11 July 2026. Where the two disagree we have followed QI, which is the underlying research Wikiquote itself points to.
Explore
Filed under
More provenance-checked quotes on the same theme, each with its reuse status.
You’re skipping our source pages — these links now open the source directly. Show them again
The author
About Unknown (a 1940s newspaper joke)
??
Unknown (a 1940s newspaper joke)
In print by July 1943 · from American newspaper humour columns
No one has ever been identified as the author. The joke belongs to a vanished ecosystem: the daily newspaper humour column, where paragraphers swapped one-liners freely, credited them to whoever had said them last, and reworked them for a local angle. Quote Investigator has traced at least six different names attached to versions of this line between 1943 and 1975 — a press officer, a jockey, a nightclub comic, a Cleveland schoolboy, an obscure acquaintance of a sports columnist, and finally Groucho Marx. That pattern is the signature of a joke with no owner.
For writers & researchers
Cite this
The primary source (Chicago)
Earliest documented instance located by Quote Investigator: The Chicago Daily News, 6 July 1943, “Personalities Plus”, ed. Ralf Gall, p. 23 — in a horse form credited to Francis Bisson. Earliest attribution to Groucho Marx located by QI: Philadelphia Daily News, 5 April 1973, p. 25.
This verification page
Quotle.info. “Who really said ‘Outside of a dog, a book is man’s best friend. Inside of a dog, it’s too dark to read’?” Last verified 12 Aug 2026. https://quotle.info/who-said/outside-of-a-dog-a-book-is-mans-best-friend-inside-of-a-dog/