Proud to have helped work on this. Happy to field any questions.

Why make the questions and AI interviewing free? This sounds too good to be true

OP here. A few of you have asked why we made these problems free. The answer is twofold, simple, and maybe even a bit underwhelming:

1) We want people to read the book (To wit, we've also made 9 chapters of the book free: http://bctci.co/free-chapters)

2) We want people to use interviewing.io

In my career, I've written a lot of stuff about hiring, and I've shared a lot of interview-related materials (e.g., full length interview replays). I hate paywalls for content, and you probably do too... and I have never regretted making it free. In my experience, putting good stuff out there is the best way to market to an eng audience.