The numbers

978 books, counted by their punctuation alone. Every chart here measures the marks; the year, genre, author and download rank only sort the books into groups. Point at a dot to see its book.

Over time

Sentences got shorter and semicolons nearly vanished. Each dot is a book at the year it first came out, and the white line is the median for every 25 years. Translations count by the year of the original. The 109 books from before 1600, Homer and Plato among them, are off the left edge.

The white line is the median of every book.

Semicolons: 14.9 semicolons per 1,000 words in 1600–1624, 1.8 in 1950–1974
05101520251600170018001900
Commas: 91.1 commas per 1,000 words in 1600–1624, 63.3 in 1950–1974
0501001501600170018001900
Words per sentence: 9.5 words per sentence in 1600–1624, 12.5 in 1950–1974
010203040501600170018001900
Question marks: 8.8 question marks per 1,000 words in 1600–1624, 5.3 in 1950–1974
0510151600170018001900
Exclamation marks: 5.8 exclamation marks per 1,000 words in 1600–1624, 2.4 in 1950–1974
051015201600170018001900
Dialogue: 13% of the words inside quotation marks in 1600–1624, 34% in 1950–1974
0%20%40%60%80%1600170018001900

Genres

Each genre's average fingerprint: every mark's share of all the marks, on the same scale as the fingerprints on the shelf. A book can sit in more than one genre.

  • Adventure

    129 books

  • Children's

    56 books

  • History and lives

    178 books

  • Horror and gothic

    31 books

  • Mystery and crime

    168 books

  • Novels

    335 books

  • Philosophy and ideas

    165 books

  • Plays

    36 books

  • Poetry

    50 books

  • Romance

    113 books

  • Science fiction and fantasy

    118 books

  • Short stories

    101 books

Authors

Can the marks name the author?

Take one book away from its author. Average the fingerprints of each author's other books, and guess whichever author's average is closest to the book. For the 64 authors with at least three different works on the shelf, that guess names the right author for 152 of 324 books, 47%. Guessing at random would be right about 2% of the time.

Each square is one of an author's books, oldest first: pink where the guess named the author. Spread is how far an author's books stray from their own average fingerprint, where 100 is the gap between two books picked at random from the shelf. The lower it is, the more alike their books are.

64 authors, most books first. The list scrolls.

Agatha Christie

The marks named Agatha Christie for 10 of 14 books. The others were taken for Edgar Wallace (3) and Arthur Conan Doyle. Spread 25.

Their average fingerprint

Over a career: their books in the order they came out (pink), against the median of the shelf's books from within 15 years of each one (dashed). Every author's chart shares one scale.
  1. The Mysterious Affair at Styles 1920
  2. The Secret Adversary 1922
  3. The Hunter's Lodge Case 1923, taken for Edgar Wallace
  4. The Missing Will 1923, taken for Arthur Conan Doyle
  5. The Murder on the Links 1923
  6. The Plymouth Express Affair 1923
  7. Poirot Investigates 1924
  8. The Man in the Brown Suit 1924
  9. The Secret of Chimneys 1925
  10. The Murder of Roger Ackroyd 1926
  11. The Big Four 1927, taken for Edgar Wallace
  12. The Mystery of the Blue Train 1928, taken for Edgar Wallace
  13. The Seven Dials Mystery 1929
  14. The Mysterious Mr. Quin 1930

Compare any two

Pick two books, two authors, or one of each. An author's numbers are the average of their books on the shelf.

Jane Austen

7 books on the shelf

Charles Dickens

14 books on the shelf

Marks per 1,000 words, except words per sentence and dialogue (the share of words inside quotation marks).
Jane AustenCharles Dickens
Semicolons13.29.7
Commas74.795.4
Colons1.21.5
Dashes and hyphens10.213.5
Exclamation marks4.67.0
Question marks3.65.8
All marks183.9249.1
Words per sentence19.916.3
Dialogue40%36%

Punctuation twins

Every book has a closest fingerprint on the shelf, named on its own page. These pairs are each other's closest match, by different authors and centuries apart.

The grammar of marks

Which mark comes next, whatever words sit between, averaged over every book. The apostrophe column is mostly contractions and possessives.

Rows: the mark before. Columns: the mark that comes next. Each number is a percentage of its row.
,."';:-?!(
,423076416211
.3923177325112
"3821167315332
'393228526331
;472557616111
:2817327329111
-2922343132221
?2312388215723
!2512329216392
(3121443251129

Marks that touch

The most common clusters of marks with nothing between them, across the whole shelf.

  1. ."373,219 times, in 929 books
  2. ,"278,575 times, in 927 books
  3. ?"158,551 times, in 845 books
  4. !"107,114 times, in 816 books
  5. .,63,617 times, in 717 books
  6. ),51,875 times, in 739 books
  7. .'43,171 times, in 725 books
  8. ,'41,043 times, in 703 books
  9. ).37,717 times, in 612 books
  10. .--33,137 times, in 423 books
  11. ...23,255 times, in 463 books
  12. .)23,235 times, in 624 books

Popularity

Do the most downloaded books punctuate differently? No. Across the 978 ranked books, the closest link between download rank and any measure is for dashes and hyphens: a rank correlation of 0.07, where 0 is no link and 1 or -1 a perfect one.

Words per sentence by download rank
010203040501200400600800download rank, most read on the left

Records

The top three books for each measure, one per author, among books of at least 2,000 words.

Most semicolons

  1. The Manual of the Botany of the Northern United States, Asa Gray: 45.3 semicolons per 1,000 words
  2. Chaucer's Works, Volume 2, Geoffrey Chaucer: 34.5 semicolons per 1,000 words
  3. The Essays or Counsels, Civil and Moral, Francis Bacon: 31.1 semicolons per 1,000 words

Most colons

  1. Cyrano De Bergerac, Edmond Rostand: 69.7 colons per 1,000 words
  2. Plays, Susan Glaspell: 36.7 colons per 1,000 words
  3. The Tempest, William Shakespeare: 31.7 colons per 1,000 words

Most commas

  1. Shakespeare's Family, C. C. Stopes: 177.4 commas per 1,000 words
  2. The Epic of Gilgamish, Stephen Langdon: 174.6 commas per 1,000 words
  3. Olympic Victor Monuments and Greek Athletic Art, Walter Woodburn Hyde: 155.7 commas per 1,000 words

Most exclamation marks

  1. Cyrano De Bergerac, Edmond Rostand: 65.0 exclamation marks per 1,000 words
  2. Murder Mask, Edgar Daniel Kramer: 36.6 exclamation marks per 1,000 words
  3. The Corsair, William Brough: 33.9 exclamation marks per 1,000 words

Most question marks

  1. I, Mars, Ray Bradbury: 22.5 question marks per 1,000 words
  2. R.U.R. (Rossum's Universal Robots), Karel Čapek: 21.9 question marks per 1,000 words
  3. A Doll's House, Henrik Ibsen: 21.2 question marks per 1,000 words

Longest sentences

  1. Discourse on the Method of Rightly Conducting One's Reason and of Seeking Truth in the Sciences, René Descartes: 79.8 words per sentence
  2. The Flower and the Leaf, Geoffrey Chaucer: 56.1 words per sentence
  3. Politics, Aristotle: 54.9 words per sentence

Shortest sentences

  1. The Waterloo Roll Call, Charles Dalton: 4.1 words per sentence
  2. R.U.R. (Rossum's Universal Robots), Karel Čapek: 4.7 words per sentence
  3. The Corsair, William Brough: 5.0 words per sentence

Most dialogue

  1. The Grand Inquisitor, Fyodor Dostoyevsky: 94% of the words inside quotation marks
  2. A Martian Odyssey, Stanley G. Weinbaum: 94% of the words inside quotation marks
  3. Utopia, Thomas More: 88% of the words inside quotation marks

Most marks

  1. Body-build and Its Inheritance, Charles Benedict Davenport: 852.4 marks per 1,000 words
  2. The Epic of Gilgamish, Stephen Langdon: 691.0 marks per 1,000 words
  3. The Works of William Shakespeare, Volume 8, William Shakespeare: 570.1 marks per 1,000 words

Fewest marks

  1. The Young Visiters Or, Mr. Salteena's Plan, Daisy Ashford: 84.6 marks per 1,000 words
  2. Limanora, Godfrey Sweven: 96.5 marks per 1,000 words
  3. The Theory of the Leisure Class, Thorstein Veblen: 101.4 marks per 1,000 words

The map

Every book, placed by its punctuation alone. Across: how many pauses (commas, semicolons, colons, dashes) a writer uses before each stop. Up: how loud it is, the share of question and exclamation marks. Click or tap a dot to open its book.

The map is wider than your screen. Swipe it sideways to see the rest.

Every book's numbers as a table
BookYearSemicolonsCommasColonsExclamation marksQuestion marksWords per sentenceDialoguePauses per stop? and ! share

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