Index, A History of the, Dennis Duncan, Penguin, 2021, 340 pps., £20

All readers of non-fiction take for granted the ability to find whatever they’re looking for quickly by recourse to an index at the end. In this playful but profound work, literary historian Dennis Duncan shows that this apparent afterthought has an intriguing history of its own – that the index is not just indispensable, but can be a work of expressive genius.

Indexing is partly instinctive – we all have a mental “index” of our possessions – and librarians in particular from Alexandria onwards have felt the necessity of organizing unwieldy information. Greek library scrolls often bore sillybos tags summarising their contents (thus ‘syllabus’), and Anglo-Saxons made alphabetical lists – but recognizable indexing only appeared once alphabets had become settled, and alphabetical ordering (long distrusted as materialist) had become acceptable. Duncan credits two thirteenth century Churchmen, Robert Grosseteste of Lincoln and Hugh of St. Cher, with the first great indexes – one a subject index, the other a concordance – search-engines of yore, reflecting their urgent need of being able to interrelate encyclopædic interests in an age of intellectual endeavour.

Indexes became increasingly sophisticated with the advent of printing, especially after page-numbering appeared in the fifteenth century. Caxton’s 1483 The Golden Legend included an index to help readers look up individual saints’ hagiographies. In Ariosto’s Orlando Furioso (1516), the English knight Astolpho works out how to escape from a fairy castle by searching in the index of his spell-book.

The index was nevertheless long controversial, like Google today – accused of allowing lazy thinkers to avoid reading texts, or being obliged to remember things. Indexes were also weaponised. The Whig historian Thomas Macaulay fretted that some “damned Tory” might index his 1848 History of England. J. Horace Round’s 1895 Feudal England enumerates alleged errors made by another medieval historian, with over a page of references under “Freeman, Professor,” like “his bias, 319, 394-7” and “imagines facts, 352, 370, 387, 432.”

William Buckley used the index to his 1966 book The Unmaking of a Mayor to goad Norman Mailer. Knowing the first thing Mailer would do on receiving a book mentioning him would be to look himself up in the index, he scribbled “Hi!” in red on the appropriate page. It was a good joke, and symptomatic of the way clever writers – from Caxton and Shakespeare via Richardson and Carroll to Nabokov and Ballard – had become interested in the index as more than an adjunct.

Duncan closes cleverly with two indexes to this book, one written by computer, and one by a professional, which proves that A.I. will never match a human compiler for subtle understanding. If the future of the index seems secure, thanks to this coruscating conspectus its past is also now much better known.

This review first appeared in the June 2021 issue of Chronicles, and is reproduced with permission