Why just have the same tired old options: "the door is locked", "the door is trapped", "the door is guarded", and "all of the above"? This is a great guide to making better doors and locks. The "story" section has a lot of useful and practical advice on doors and locks. It's informative without being needlessly long. The authors get right to the point and move on. What's better is that they included some great tables for when you need a random door or lock problem. These include problems with the key, complications with the lock, problems with the environment, and more. This is a great resource, and very educational for improving the role-playing experience.