Eh...forgive me for saying, but this is a bit of a cop-out. Especially where the author notes that you then have to supplement this "one question" with 20 min o

Eh...forgive me for saying, but this is a bit of a cop-out. Especially where the author notes that you then have to supplement this "one question" with 20 min of follow-up. It's essentially saying "the only interview question that matters is having an interview". I'm not saying that this doesn't work. I've been through my fair share of interviews on both sides of the table, and focusing an interview on various dimensions of a single project is a far, far better strategy than the typical haphazard array of semi-related questions on people skills and technical ability. Really, I think it's not even so important that you focus on the "that you're most proud of" part. This tack would work just as well, I suspect, with the interviewees second or third most notable accomplishment. What's important is that it is a project of sufficient size that you can ask the follow-ups, and in doing so construct a consistent picture of the candidate as an employee. If you really want one question to get the most information from someone, my goto has always been: "What is your current favorite language/framework/technology stack? What do you hate about it?" Ok, so technically that's two (or one two-part question), but I've found that this question will very quickly reveal how able someone is to think critically and to assess all facets of the decisions that they make.