The row erupted at the 61st international Frankfurt Book Fair, a major annual literary event.
A literature professor from Germany's Heidelberg University responded sharply to Google Books, a massive project by the US group to give the world access to books otherwise hard or impossible to obtain.
Describing Google's claims as "just a whole garbage of hysterical propaganda," Professor Roland Reuss warned of a threat to traditional publishing, saying at a forum on the issue: "You revolutionise the market but the cost is that the producers of goods in this market will be demolished."
Google's head of Print Content Partnerships in Britain, Santiago de la Mora, responded: "We're solving one of the big problems in the world; that is books are pretty much dead in the sense that they are not being found."
“We're bringing these books back to life, making them more visible to 1.8 billion Internet users in a very controlled way," de la Mora said.
Google Books is facing big legal problems in the United States, Europe and elsewhere around the globe over the key issue of copyright laws.
German Chancellor Angela Merkel has urged that European Union copyright be protected and the German and French governments have filed objections to a US court settlement that a judge has ordered be revised.
Google pitches its plan as an effort to archive as much of the world's knowledge as possible in one (cyber) space, the first such attempt since the Library of Alexandria.
It is to be paid for mainly by online advertising although some out of print books could also be sold using one-off printing and binding machines.
The process of making books available on the Internet is known as scanning or digitisation, a process which although already old hat for many, has gripped the publishing sector as something which will change its world.
A connected topic also raising interest in Frankfurt is that of portable readers of electronic books, or e-books - books that can be downloaded from or read on the Internet - which are reportedly set for brisk sales in the upcoming holiday shopping seasons.
Google has raised the pressure on its Internet rival, Amazon.com, with a new service called Google Editions.
Google wants to offer e-books for use on all devices with web browsers, from mobile phones to desk-top computers, challenging Amazon's Kindle e-book reader which forces buyers to buy books through the company.
Google said it and partners planned to have around half a million book titles available by the middle of next year.
Laurent Picard, co-founder of Bookeen, which makes the Cybook Opus reader for e-books, forecast that Google and Amazon "will have a great power over publishers" and could begin to influence prices as paperback books slowly disappeared.
Google said publishers would set the price of works sold and share 45 percent of the total with authors. Google and online retailers would split the rest.
The European Union also used the book fair to launch the EU Bookshop's digital library, making more than 50 years of documents in about 50 languages available for free via the Internet.
Individuals, companies and isolated libraries from northern Sweden to the mountains of Bulgaria, and anyone from Australia to Zambia can download files dating back to 1952 when six countries created what is now the 27-member EU.
"With the digital library, we have total transparency" of EU legislative and cultural publications, Commissioner for Multilinguism Leonard Orban told AFP at the Frankfurt Book Fair on Sunday.
The project also underpins "the commitment of the European Union to preserve and encourage the history of the union in its linguistic diversity," he added.
The library's oldest document is a speech by Jean Monnet to inaugurate the High Authority of the Coal and Steel Community, the EU's precursor.
From four official languages at its start, the union now counts 23, but some publications are also available in Chinese, Russian and around 20 other languages.
The library currently includes around 140,000 publications, and 1,500 "born digital" ones are added each year. More pre-digital documents will also scanned into the system.
Roughly 110,000 publications or 12 million pages -- the equivalent of four kilometres (2.5 miles) of bookshelves -- were scanned from EU archives from February 2008 at a cost of about €2.5 million.