Melanie Piper knows how important the ending is to any book -- including the part that comes after the author has finished.

Piper, 34, is a book indexer. Her job is to distill a book into just a few pages, making it easier for readers to figure out if the information they want is there.

Like many professional indexers, Piper has areas of expertise. Her master's degree in sociology makes her a natural to handle books in that field, as well as history and current events. Her years of working in health care, as a nurse, also qualify her to work on medical and self-help books.

Piper, who is president of the New England chapter of the American Society of Indexers, said that kind of knowledge is helpful in being a good indexer. "You know the jargon, you know who's important."

However, Piper said the chief trait of a good indexer is a love of reading. Indexers also must be open-minded about the topics. "I've read books I never would have picked myself."

Piper, who lives in Franklin, Mass., has been a freelance indexer since 2001. The hours are flexible, she said, but the deadlines can be fierce, especially if the book has fallen behind in other steps of the production process.

"The indexer is the last link in the chain of the publishing process."

-- Mary Ellen Slayter