As Carol Roberts says, an index can make the difference between a nonfiction book and a well-dressed nonfiction book. It is the necessary accessory to set any book apart from its peers, to rise to the occasion of excellence.
I recently indexed a book on US national security strategy, from 1920 through 2010. The index was 24 single-spaced pages long, as you might imagine when dealing with such a subject.
The index for the book, in order to be useful to any reader, had to be extremely detailed. It had to include all of the US administrations, the countries involved in US national security strategy discussions, and all of the actors.
To begin, I did a general swipe through the book, indexing the general terms and players: treaties, countries, leaders, etc. Then, I went page by page through the book, fine-tuning the topics and the indexed items.
For example, initially, I had the Eisenhower administration. By the end of my indexing task, I had
Eisenhower administration, 85
bilateral and multilateral alliances, 102, 107, 114, 118
building interstate highways, 101
containment of China, 107, 108
crisis in West Berlin, 113–114
damaged relations with Britain and England, 112
decrease in conventional forces, 102–104, 114, 118
downslide in Europe, 113–115
drawn into Middle East affairs, 110, 111, 118
effective NSC staff, 117
end of Korean War, 107
entry of Germany into NATO, 104
SEATO (Southeast Asia Treaty Organization), 102, 104
strategic bilateral agreements in Asia, 107
sustained domestic growth, 101
vital bipartisanship in US foreign policy, 85, 118
waning years, 113–115
Eisenhower Doctrine, 102, 110, 112
Eisenhower Years (1953–1961), 100–112
Eisenhower, Dwight D., 56, 100–101
as SACEUR for NATO, 88–90
D-Day command, 61
wise presidential leadership, 101, 116
These topics and subtopics listings made the information much easier to access quickly and intelligently. The more detail you can provide for the readers, the more powerful the index will be. And the easier you make it for readers to determine what each mention of a topic contains, the happier the reader will be.
For example, for Saddam Hussein, who had a small part in the book, I could simply have listed:
Hussein, Saddam, 6, 253, 266-268, 270, 276, 286, 322–324, 336, 361-363, 373.
But this would have required the reader to search each page or page range to find the particular information they were interested in. A better index was created using subtopics:
Hussein, Saddam, 6, 253, 266, 286, 322–324, 336. See also Desert Storm Campaign
“mother of all battles”, 270
brutal dictator, 361
menace to Middle Eastern security, 361, 362–363
resistance to diplomacy, 268, 270, 323, 363–364
survival of regime after Desert Storm, 276
threat if allowed to remain in power, 373
threat to Saudi Arabia, 267
threats against Israel, 267
UN Security Council Resolution 1441, 364
WMD (weapons of mass destruction). See WMDs (weapons of mass destruction)
With these entries, a reader could much more quickly find specific topics about Saddam Hussein.
Subtopics are key in a superb index. Creating pertinent subtopics requires a great deal of attention to detail, and the ability to organize, but an index rich in subtopics adds great value to any manuscript.