For nearly 30 years now, an interesting philosophical problem has been developing and taking shape, but not in the philosophical literature. Interactive epistemology (or interactive knowledge) is a branch of logic dealing with shared knowledge, but it has been dealt with nearly entirely in the economic and computer science literature. My purpose in the current article is to introduce some of the progress that has been made on this topic over the course of the last 30 years, as well as make clear what are some of the more interesting philosophical problems associated with this, along with some of the solutions offered thus far.