Editorial Note: The following article by J M. Greene discusses one view of “The Parker Challenge,” which asks whether magnetospheric plasma physics, for example, can best be understood in terms of magnetic fields and flows (the B,v paradigm), or in terms of electric fields and currents (the E,j paradigm). As with any such challenge, the resultant debate can be quite heated. Nevertheless, in my opinion, this type of debate will ultimately provide greater insight into the physics of space plasmas. This debate is not well suited for journals such as the Journal of Geophysical Research, since it is necessarily more anecdotal in nature, whereas Eos provides an appropriate forum. Motivated by J. M. Greene's article, I am therefore soliciting brief articles from members of the space physics and aeronomy community that demonstrate the usefulness of either paradigm. To this end, anyone who wishes to submit a brief contribution to this debate should send me an e-mail message to that effect. I will coordinate such submissions for publication together in a future issue of Eos.