Google has started integrating its popular mapping service with its controversial books search engine to let people plot on maps references to places they find in books.

Now, book entries in Google's Book Search may include a section called "Places mentioned in this book." The section includes a map from Google Maps with pins indicating places included in the text. Below the map is a list with the name of the places, linked to the pages in which they are mentioned and an excerpt from the text.

Some books whose entries include this new feature are

Jules Verne's Around the World in Eighty Days , Leo Tolstoy's War and Peace and Charles Sanford Terry's Bach: A Biography .

"When our automatic techniques determine that there are a good number of quality locations from a book to show you, you'll find a map on the 'About this book' page," wrote David Petrou, a Google software engineer, in the official Book Search blog on Thursday.

"We hope this feature helps you plan your next trip, research an area for academic purposes, or visualize the haunts of your favorite fictional characters," he wrote.

Google's Book Search service is one of the company's most controversial and the target of copyright-infringement lawsuits in the U.S. and abroad. Authors and publishers have taken issue with Google's project to scan books from libraries without always obtaining permission from copyright holders. Google argues that its actions are protected by the fair-use principle because it only displays text snippets from in-copyright books. Critics say the mere act of making a digital copy of a book, storing it on a server, and creating a full-text index of its content for business purposes, without permission, constitutes copyright infringement.