When Mr. Whitehead searched the site, he found that all of his books except for the most recent, “The Nickel Boys,” were available free. After he asked Internet Archive to remove the works they were taken down, Mr. Whitehead said in an email.

The author and illustrator Jarrett J. Krosoczka said he was not aware that many of his books were available free on the archive until his literary agent contacted him last week. Mr. Krosoczka said that, like many authors, he was even more dependent now on his royalties to make a living because the money he was receiving from speaking events has dried up during the crisis.

“I was very disappointed to find my books illegally uploaded to this service,” he said. “This is the intellectual property that supports my family.”

While Internet Archive calls itself a digital library, it operates differently from public libraries that have e-book lending programs. Public libraries get licenses from publishers for the e-books they lend, and publishers receive payments, according to the terms that are set. Internet Archive doesn’t get licenses from publishers but instead relies on donated or purchased books or copies it acquires through collaborations with physical libraries. The books are then scanned and made available for one borrower at a time, for 14 days. With that restriction removed, the archive is now operating more or less like a free digital book site.