"Those who use the book as a part of the research for ancestors can well afford the relatively few hours necessary to read the entire book..."
Now there's an interesting thought.
The 1958 genealogy of the Kile family has no index. In place of the index is a one page statement "Why No Index."
The author makes some good points. Indexing a book in 1958 was a more intensive process than it is today.
And reading the entire book is never a bad idea--just looking at the one page that mentions the person of interest can easily cause the researcher to overlook other significant information.