Why non-fiction books need their indexes

I'm coming across increasing numbers of new non-fiction books that lack an index. No doubt it's done to save costs, but I wonder if it's a false economy.

Not only is a book without an index less satisfactory after you've bought it, but that lack makes you less likely to buy it in the first place.

I can't be the only person who, faced with a promising new title in a bookshop, turns to the index and looks up a couple of relevant topics I know something about. What the books says about them gives me an idea of the author's thoroughness, judgement and originality.

Without an index it's much harder to gain this insight, which makes an impulse purchase less likely.

Besides, the absence of an index means there are none of the juxtaposed entries I so enjoy.

The other day I turned up a Liberal Democrat Voice post from 2010 in which a number of bloggers made their choice of Christmas books.

My choice was Electric Eden by Rob Young, which is a history of the folk rock genre. I ended by saying:

The book has a wonderfully complete discography to guide your own exploration of folk and folk rock, and the most engrossing index I have ever come across. Richard Jefferies stands next to Jefferson Starship. Traffic next to Thomas Traherne. Steve Winwood next to Gerrard Winstanley, It reads like notes towards my own vision of Britain.

But the real master of unlikely couplings in indexes is Mike Brearley. In included a collection of finest work in one of my JCPCP columns:

• Archer, Jofra/Aristides the Just;
• Bowlby, John/Boycott, Geoff; 
• counter-transference/Cowdrey, Colin;
• Gower, David/Gramsci, Antonio;
• idée fixe/Illingworth, Ray;
• Muralitharan, Muttiah/Murdoch, Iris;
• Snow, C.P./Snow, John;
• Thomson, Jeff/Thorndike, Sybil;
• Trueman, Fred/Trump, Donald;
• Wittgenstein, Ludwig/Woakes, Chris.