Spotify Technology’s big leap into audiobooks is facing a backlash from U.S. authors who fear they’ll be short-changed by the streaming giant.

Spotify began offering complimentary audiobooks to millions of customers in October as part of their monthly subscriptions. All of the so-called Big Five publishers signed on, with Penguin Random House saying it was "excited” to place titles on the service.

But not everyone in the book industry is thrilled, including Bradley Tusk, a New York-based venture capitalist, author and bookstore owner whose political advocacy firm Tusk Strategies is rallying authors who worry that the shift to streaming will make it even more difficult to earn a living.