This is wide open for debate but I'll put in my two cents (since you asked): this volume might be the most important in the study of "anti-gravity" science. And I'm not talking about "ion wind" or lifter technology. The Basics book touches on what I'm talking about, and it is further detailed in this volume.

MHD may be another key technology, but there are serious issues with MHD and Electrogravitics. Namely, the incredible amount of energy it would take to power a craft that relies on these tech's. Something else is at work in "anti-gravity" that either doesn't require as much power or enhances MHD/Electrogravitics. I don't want to spoil the ending so just get this volume and you'll see what screams for more research.