Oyster a Netflix-style service for e-books, has brought on its first chief financial officer, Jeannie Mun.

Before joining Oyster, Mun spent a lot of time in the ad world, having recently served as CFO at ad company MediaMath, and before that working as vice president of finance and strategy at ad software company Operative.

So why join an e-book startup? Mun said she was starting to think about “the next stage of my career,” and after meeting with Oyster CEO Eric Stromberg, she became “more and more excited” about finding a role that combined her experience in finance with her love of book, and also about how the subscription model and the growth of mobile devices has led to an “amazing amount of transformation in the industry.”

Oyster charges $9.95 a month for unlimited access to a library of more than 1 million titles. Mun said the company is working to create “an on-demand, all-you-can-eat model that is really data driven” — by building out its data science team, Oyster can personalize its recommendations and “make it a wonderful experience for every single user.”

At the same time, it faces competition from similar services, namely Scribd, as well as Amazon’s Kindle Lending Library. Recent wins include signing up “Big Five” publisher Macmillan (along with Scribd) and adding J.K. Rowling’s Harry Potter novels. The company says its subscribers are now reading 100 million pages each month.

Mun suggested that Oyster has been largely product-focused until now, with “relatively little outbound efforts” aimed at increasing the subscriber base — so hiring a CFO is part of a broader shift towards growth mode.

“What I’ve always focused on is helping companies grow, and really thinking about what the future holds, and what scenarios should we evaluate today to really set us up for success to tomorrow,” she said.

Oyster is also announcing that former Netflix CFO Barry McCarthy has agreed to become an advisor. McCarthy joined Spotify’s board last fall.