Jan Tschichold ‘Penguin Composition Rules’.
Footnotes should be set two points smaller than the text. Indent the first line of these with the same number of points as the paragraphs in the text matter. Use equal leading between all lines of footnotes, use the same leading as in the text matter, and put 1-2 point lead underneath the last line in order to get register with the normal lines.
For the numbering of footnotes use normal figures followed by a full point and an en quad. These figures may run either throughout the chapter, or even through the whole book, according to the special instructions given by the typographer.

Folios
These should, as a rule, be set in the same size and face as the text, and in Arabic numerals.
Pagination should begin with the first leaf in the book, but the first folio actually appearing is that on the verso of the first page of the text.
When there is preliminary matter whose extent is unknown at the time of making up the text into pages, it is necessary to use lower-case roman numerals, numbered from the first page of the first sheet. The first actually appearing cannot be definitely stated, but may be on the acknowledgments page, or at latest on the second page of the preface. In this case, the first Arabic folio to appear will be ‘2’ on the verso of the first text page.
Folios for any text matter at the end of the book, such as index etc., should continue the Arabic numbering of the text pages.

The Printing of Plays
The same rules should apply to the printing of plays as to the printing of prose. Names of characters should be set in capitals and small capitals. The text following is indented. Stage directions should be in italics, enclosed in square brackets. The headline should include the number of the act and the scene.

The Printing of Poetry
For printing poetry use type of a smaller size than would be used for prose. All composition should be leaded and the words evenly spaced with middle spaces. The titles should be centred on the measure, not on the first line. The beginning of each poem may be treated as a chapter opening, with small capitals, etc.
Extra leading, especially between verses of irregular length, may often be misleading, as it is impossible to see whether the verse ends at the bottom of the page or not. The safest way of recognizing the poet’s intention is to indent the first line of every new verse, after which leading is not really necessary. Therefore, the first line of the second and following verses should be indented, unless the poet has indicated a shape not allowing for indentations.

Make-up
Books should, with certain exceptions, be made up in the following order:
I. Preliminary pages: 1, half title; 2, frontispiece; 3, title; 4, Imprint or date of publication; 5, dedication; 6, acknowledgments; 7, contents; 8, list of illustrations; 9, list of abbreviations; 10, preface; 11, introduction; 12, errata.
II. The text of the book.
III. Additional matter: 1. appendix; 2. author’s notes; 3. glossary; 4. bibliography; 5. index.
The above should each begin on a right-hand page, imprint and frontispiece excepted. As a rule, chapter headings should be dropped a few lines.
The preliminary pages should be set in the same face and style as the book itself. Avoid bold faces.
The index should be set in two or more columns and in type two points smaller than the text. The first word of each letter of the alphabet should be set in small capitals with capitals.

–Jan Tschichold (1947)

Text Composition
All text composition should be as closely word-spaced as possible. As a rule, the spacing should be about a middle space or the thickness of an ‘i’ in the type size used.
Wide spaces should be strictly avoided. Words may be freely broken whenever necessary to avoid wide spacing, as breaking words is less harmful to the appearance of the page than too much space between words.
All major punctuation marks – full point, colon, and semicolon – should be followed by the same spacing as is used throughout the rest of the line.

Indenting of Paragraphs
The indent of the paragraph should be the em of the fount body.
Omit indents in the first line of the first paragraph of any text and at the beginning of a new section that comes under a subheading. It is not necessary to set the first word in small capitals, but if this is done for any reason, the word should be letter-spaced in the same way as the running title.
If a chapter is divided into several parts without headings, these parts should be divided not only by an additional space, but always by one or more asterisks of the fount body. As a rule, one asterisk is sufficient. Without them it is impossible to see whether a part ends at the bottom of a page or not. Even when the last line of such a part ends the page, there will always be space for an asterisk in the bottom margin.

Punctuation Marks and Spelling
If this can be done on the keyboard, put thin spaces before question marks, exclamation marks, colons, and semicolons.
Between initials and names, as in G. B. Shaw and after all abbreviations where a full point is used, use a smaller (fixed) space than between the other words in the line.
Instead of em rules without spaces, use en rules preceded and followed by the word space of the line, as in the third paragraph above.

Marks of omission should consist of three full points. These should be set without any spaces, but be preceded and followed by word spaces.
Use full points sparingly and omit after these abbreviations: Mr, Mrs, Messrs, Dr, St, WC2, 8vo, and others containing the last letter of the abbreviated word.
Use single quotes for a first quotation and double quotes for quotations within quotations. If there is still another quotation within the second, return to single quotes. Punctuation belonging to a quotation comes within the quotes, otherwise outside.
Opening quotes should be followed by a hairspace except before A and J. Closing quotes should be preceded by a hairspace except after a comma or a full point. If this cannot be done on the keyboard, omit these hairspaces, but try to get the necessary attachment.
When long extracts are set in small type do not use quotes.
Use parentheses () for explanation and interpolations; brackets [] for notes.
For all other queries on spelling, consult the Rules for Compositors and Readers at the University Press, Oxford, or Collins’s Authors’ and Printers’ Dictionary.

Capitals, Small Capitals, and Italics
Words in capitals must always be letter-spaced. The spacing of the capitals in lines of importance should be very carefully optically equalized. The word spaces in lines either of capitals or small capitals should not exceed an en quad.
All display lines set in the same fount should be given the same spacing throughout the book.
Use small capitals for running headlines and in contents pages. They must always be slightly letter-spaced to make words legible.
Running headlines, unless otherwise stated, should consist of the title of the book on the left-hand page, and the contents of the chapter on the right.
Italics are to be used for emphasis, for foreign words and phrases, and for the titles of books, newspapers, and plays which appear in the text. In such cases the definite article ‘The’ should be printed in roman, unless it is part of the title itself.
In bibliographical and related matter, as a rule, authors’ names should be given in small capitals with capitals, and the titles in italics.

Figures
Do not mix old style text composition with modern face figures. Either hanging or ranging figures may be used if they are cut in the fount used for the text.
In text matter, numbers under 100 should be composed in letters. Use figures when the matter consists of a sequence of stated quantities, particulars of age, etc. In dates use the fewest possible figures, 1946-7, not 1946-1947. Divide by an en rule without spaces.

References and Footnotes
The reference to a footnote may be given by an asterisk of the fount body, if there are only a few footnotes in the book, and not more than one per page. But if there are two or more footnotes per page, use superior fraction figures preceded by a thin space.
Do not use modern face fraction figures in any old style fount. Either hanging or ranging fraction figures may be used provided that they are in harmony with the face used for the text. For books composed in any old face letter, we recommend Monotype Superior Figures F627, to be cast on the size two points below the size of the face used.