This is a post I should have made a while back.
Many of you know james_nicoll from here and perhaps elsewhere -- actual conventions, Usenet, etc. -- and know that he's one of the most consistently... INTERESTING posters anywhere. Besides his long sequence of Nicoll Event adventures, James happens to be one of the most voracious readers of SF/F in the world, partly because he gets paid to do it (he's a primary reader for the SFBC and others), but partly because he is a fan of the genre in all its glory and ignominy.
He's also a very EDUCATED reader and one who has a wide variety of referenced knowledge on vital facts and considerations for would-be SF/F writers, especially those who might want to attempt the hard-SF subgenre.
James gave me, in particular, several useful pointers in writing Boundary and Threshold; the most significant ones probably being pointing me in the direction of Robert Sheldon's "Dusty Plasma" drive concept, which I subsequently used for the Bemmie vessel in Threshold, the need and use of magnetic-based shielding for charged-particle radiation (especially near Jupiter!) and helping me understand the use of the Oberth maneuver. (Note that any failures in my attempt to use these, or any other, concepts should be laid entirely at my feet and not at any of the people I have consulted). There were other similar, though perhaps less important, points that his comments (and sometimes rants about other books) gave to me to keep in mind while writing. Yes, he's acknowledged in Threshold, but I felt a somewhat more detailed thanks was called for.
So thanks for your help, your anecdotes, and your Net.Presence, James!