When one begins to summarize the conference proceedings dealing with the neutral and ion chemistry of the E region, one becomes forcefully aware of the spectacular advances that have been made in this area during the past decade. This conference has well demonstrated that these advances are continuing, and that there is yet a wide range of problems to be overcome. Both these aspects will be discussed briefly below.
Some consideration will, first of all, be given to the neutral chemistry at E-region heights although it cannot be separated realistically from the ion chemistry. Most of the proceedings in this area were devoted to the chemistry of odd nitrogen and it now seems clear that the major problems are associated with uncertainties related to the production and loss of N(2D).