I applied to Cengage through an agency with a CV and cover letter, and was asked to send a second, more detailed cover letter once they expressed interest in meeting me. They later moved the interview date back a week with a few days' notice.
The interview itself was a pleasant experience, with friendly staff and in a nice location. I got the sense that I would enjoy working there. I answered about ten questions: a mix of behaviourals, knowledge about the company, and imaginary scenarios. There were also some specific questions about technical aspects of the job, such as dealing with rights and permissions.
After the initial questions, there was an isolated twenty-minute proofreading/editing test which involved correcting and rewriting a blurb for an imaginary textbook. The interviewers then came back, had me talk them through my suggested changes, and offered to answer any questions I had.
While I didn't receive an offer, their feedback was quick, polite, and largely very positive.