History of sentence spacing

Typesetting in all European languages enjoys a long tradition of using spaces of varying widths for the express purpose of enhancing readability.

American, English, French, and other European typesetters' style guides—also known as printers' rules—specified spacing rules which were all essentially identical from the 18th century onwards.

MacKellar's The American Printer was the dominant language style guide in the US at the time and ran to at least 17 editions between 1866 and 1893, and De Vinne's The Practice of Typography was the undisputed global authority on English-language typesetting style from 1901 until well past Dowding's first formal alternative spacing suggestion in the mid-1950s[citation needed].

Additionally, spaces were (and still are today) varied proportionally in width when justifying lines, originally by hand, later by machine, now usually by software.

[5] For example, T. S. Eliot typed rather than wrote the manuscript for his classic The Waste Land between 1920 and 1922, and used only English spacing throughout: double-spaced sentences.

[16] The underlying reasons were:[15] Before the First World War virtually all English-language books were printed following standard typesetters' spacing rules.

In 1941, IBM introduced the Executive, a typewriter that used proportional spacing by breaking each cell of the grid into fifths.

The introduction and widespread adoption of non-commandline desktop publishing software on personal computers in the mid-1980s eliminated previous cost-restrictions that had helped fuel the switch to single-spacing.

Despite this, resistance to double-spaced sentences started to grow among English-language professional designers and typographers as they became more directly involved with typesetting.

With regard to spacing, modern designers are retracing the steps of the 19th-century design-led typographer William Morris.

However, the reason Donald Knuth gave for creating the TeX typesetting system was his dismay on receiving the proofs of a new edition of his book The Art of Computer Programming at the unreadability of the then new close-fitted phototypesetting technology, which he described as "awful" due to its "poor spacing".

During the fifteenth century, when thin leads and graduated spaces were almost unknown and but little used, the reading world had its surfeit of close-spaced and solid typesetting.