How much of a copyrighted book can I display in a web app?

Question

Google Books and Amazon both display significant portions of copyrighted material for free. In the case of Google, there is an option to select books based on the qualifications

• Any books
• Preview available
• Google eBooks
• Free Google eBooks

Some texts like Early History of Wine Production in California have no eBook available but provide Snippet view. Others, like History of Wine Words: An Intoxicating Dictionary of Etymology and Word Histories from the Vineyard, Glass, and Bottle provide no preview at all, and have no eBook available.

This stimulates the questions:

1. Is this difference of previewing dependent on copyright or technology (i.e., have they not scanned the text or can they not get permission)?
2. More importantly: what are the legal ramifications of digitizing a text and making it searchable? How much of the search results can I display without being affected by copyright law?

I very much want to allow the users of my web app to be able to search for lines in any text on my platform. If they search "It was a bright cold day in April, and the clocks were striking thirteen." I would like for the result to be the first line of Nineteen Eighty-Four and display some context (i.e. the surrounding lines).

What do I need to be legally aware of for this?

Clarification: I am not using Google or Amazon's services. I will obtain the books myself, even digitize them myself if I have to.

My question is specifically about fair use. I brought up Google and Amazon to describe similar web behavior.

Issues I see:

• How many lines of context around an indexed line can I display within fair use guidelines?
• Is there a problem with the fact that a user could do the following:
  1. Search the first line of a book.
  2. Read the context blurb (say 5 lines, if that is legal).
  3. Search the last line of the context from the previous search.
  4. Read that context blurb.
  5. Search the last line from the previous search.
  6. Continue until the end of the book?

It is an unrealistic case, but is it legally problematic for my app to not prevent this?

Answer 1

I very much want to allow the users of my web app to be able to search for lines in any text on my platform.

That means you are accessing Google and Amazon's data - whole books, snippets, excerpts - via your own App, and as such you need to read each services' TOS for the restrictions on using their services in such a way. Briefly, you can't legally access their data in an automated (and legal) way without expressed permission from those services. Read each services' TOS.

Those services either hold copyright on the formats of the works and books they have scanned, or they have gotten copyright permission from the copyright holders to digitize, or are presenting excerpts and snippets that fall under Fair Use (U.S. Copyright Office). Google uses a legal precedent to scan and use copyrighted material for their service (though not everyone is happy about it); read Google Books just won a decade-long copyright fight - The Washington Post.

What you need to be "legally aware" of is that you need permission from those services to use the data for your App. Those services can take legal action against you if you use their services in violation of their TOSs, no matter the length of the excerpt you use, how you search or how you present search results in your own App.

Edit:

I will obtain the books myself, even digitize them myself if I have to.

That could put you in direct legal jeopardy of copyright infringement, depending on jurisdiction and international laws (see Berne Convention - Wikipedia), when you digitize an entire book without permission. It doesn't matter how many lines you display in your App in an attempt to fall under Fair Use; you have already scanned and stored the entire work on a server for your App to access.