Outside of a Dog, a Book is Man’s Best Friend. Inside of a Dog, It’s Too Dark to Read

Groucho Marx? Jim Brewer ? Mary Stuart? Anonymous?

Dear Quote Investigator: You have researched some quotes credited to Groucho Marx, so I am hoping that you will be able to look into a saying that interests me. I work in a library and have long enjoyed the following quip:

Outside of a dog, a book is a man’s best friend. Inside of a dog, it’s too dark to read.

I have seen it on websites associated with libraries where the saying is credited to Groucho. Is this attribution accurate?

Quote Investigator: The earliest attribution to Groucho that QI has located occurred in 1974 at a museum exhibit celebrating words and reading. But the provenance of the quip can be traced further back to the 1950s. Top-notch researcher, John Baker, located the earliest known instance of this joke in an issue of Boys’ Life magazine dated 1954. In this initial appearance the quip is credited to Jim Brewer and not to Groucho Marx.

The quip appeared in a regular feature of Boys’ Life that requested readers to send in humorous material. A subset was then selected to appear in a section called “Think and Grin”. The attribution listed after the quote likely corresponds to the name and location of the individual who sent in the joke. The wording in February 1954 is permuted slightly: 1

A book is man’s best friend outside of a dog, and inside of a dog it’s too dark to read.—Jim Brewer, Cleveland, O.

Groucho Marx was active as a comedian before 1954, and it is possible that he told the joke before this date. The Boys’ Life communicant may have heard the gag directly or indirectly from Groucho, but QI has not yet located any evidence to support this possibility. Alternatively, the quip may have been reassigned to a prestigious comedian such as Groucho to enhance its popularity.

In 1965 the syndicated columnist Mary Stuart printed an instance of the quip in her column called “Heard and Seen”. The punchline was not placed between quotations marks: 2 3

A writer says, “A book is man’s best friend — outside of a dog.” I imagine inside of a dog is too dark to read.

The Yale Book of Quotations and the Oxford Dictionary of Humorous Quotations both list this witticism under Groucho Marx and provide citations dated 1987 and 2000 respectively. 4 5

The first attribution to Groucho located by QI appears in the Los Angeles Times in 1974 in a review of a museum exhibit titled “Word Show–An Experience in the Possibilities of Language”. The author describes the interactive displays: “I saw two boys sliding down a big red plywood structure in the shape of a capital A.” He also discusses the words and phrases on the walls: 6

Some were riddles, some aphorisms:

Why are elephants wrinkled? Did you ever try to iron one?

Outside of a dog a book is man’s best friend because inside of a dog it’s too dark to read.—Groucho.

In 1978 a text, “The Art Museum as Educator”, examines the same show from a pedagogical viewpoint. The Groucho quote is presented but the wording given is slightly different: 7

“The Word Show,” January through March 1974, was a cooperative venture of the staff artists and the gallery’s curator. The result was a wild and educational exhibit based on the origin, form, perversity, and delight of words. It was full of verbal and visual puns, jokes, riddles, and images. For example, from Groucho Marx,

Outside of a dog, a book is man’s best friend because inside of a dog is too dark to read.

The exhibit’s organizers wanted to make children aware of language, of words in combination, and of the sound and shape of words and letters.

In conclusion, the attribution of the quotation to Groucho is uncertain. The earliest instance known to QI does not mention him, but by the 1970s he is being given credit for the quip. QI thanks you for your question, and notes that some ebook readers do not require external illumination, e.g., the iPad. If one is swallowed Jonah-like by an enormous mammal one may continue to read unimpeded.

Image Notes: Photo of shelves of books from TryJimmy on Pixabay. Image of Bernese Mountain Dog from Beatriz57 on Pixabay. Promotional postcard showing Groucho Marx via Wikimedia Commons. Images have been cropped and resized.

(This question was inspired by a discussion on the ADS mailing list. Many thanks to the participants. Special thanks to Laurence Horn for initiating the discussion.)

Update History: On March 13, 2015 the 1965 citation was added and the top image was redone.


  1. 1954 February, Boys’ Life, Think and Grin, “Man’s best friend” joke attributed to Jim Brewer, Page 78, Column 1, Boy Scouts of America, Inc. (Google Books Full View) link
  2. 1965 January 13, The Austin News (The News), Heard and Seen by Mary Stuart, Quote Page 8, Column 3, Published by Community Publications, Inc., Chicago, Illinois. (Newspapers_com)
  3. 1965 January 13, The Garfieldian (Suburbanite Economist), Heard and Seen by Mary Stuart, Quote Page 8, Column 3, Published by Community Publications, Inc., Chicago, Illinois. (Newspapers_com)
  4. 2006, The Yale Book of Quotations by Fred R. Shapiro, Groucho Marx, Page 498, Yale University Press, New Haven.
  5. 2008, Oxford Dictionary of Humorous Quotations edited by Ned Sherrin, Animals, Page 12, Oxford University Press, New York. (Google Books preview) link
  6. 1974 January 28, Los Angeles Times, A Fascinating Play on Words by Jack Smith, Page D1, Los Angeles, California. (ProQuest)
  7. 1978, The Art Museum as Educator edited by Barbara Y. Newsom, Adele Z. Silver, Page 369, University of California Press. (Google Books limited view; Verified on paper) link

2 thoughts on “Outside of a Dog, a Book is Man’s Best Friend. Inside of a Dog, It’s Too Dark to Read”

  1. Your article on Jim Brewer’s quote about the inside of a dog contains some typos. The column in which Mr. Brewer’s comment appears was published in February, 1954, not 1958.

  2. Thanks very much. I’ve changed the date to 1954 in the body of the post. The bibliography listed the correct date, at least. I appreciate your help and apologize for the error

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