More than 30 years after the First International Indoor Climate Symposium, ten researchers from the USA, Slovakia, Sweden, and Denmark gathered to review the current status of indoor environmental research. We initiated our review with discussions during the 1-day meeting and followed that with parallel research and writing efforts culminating with internal review and revision cycles. In this paper, we present our choices for the most important research findings on indoor environmental quality from the past three decades followed by a discussion of the most important research questions in our field today. We then continue with a discussion on whether there are research areas for which we can 'close the book' and say that we already know what is needed. Finally, we discuss whether we can maintain our identity in the future or it is time to team up with new partners.In the early years of this field, the accumulated knowledge was small and it was possible for any researcher to acquire a complete understanding. To do so has become impossible today as what we know has grown to exceed the learning capacity of any person. These circumstances challenge us to work collectively to synthesize what we do know and to define clearly what remains to be learned. If we fail to do these things well, we risk repeating research without memory, an inefficiency that we cannot afford.