The early days of space travel - the tragic deaths, the explorers who disappeared without a trace, the many heroisms- were now relegated to a few pages in history textbooks. The Solar System, from Mercury out to the cometary Oort cloud, was as thoroughly domesticated and familiar as anyone's back yard. But other frontiers still beckoned, as distant as the farthest stars themselves, and humankind swarmed out across the galaxy at speeds many times that of light, but still only an amoeboid crawl in comparison to the vast breadth of the galaxy. And once again the statement by a largely-forgotten 20th century scientist was proven true: the universe is not only stranger than we imagine-it is stranger than we can imagine. Stories of interstellar voyagers confronting the infinite by: Gregory Benford, Eric Flint & Dave Freer, James P. Hogan, Debra Doyle & James MacDonald . . . and more.
So far I have only read the Gregory Benford novella "Beyond Pluto". It must me related somehow to at least three other of Benford's pieces of fiction - Iceborn, Proserpina, and Sunborn given the names of some of the characters being the same among all three and the names of some of the et's. But I am unsure of where it comes in the chronology though it may be the last of the four. I think Iceborn is a expansion of Proserpina if I remember correctly. It's all very interesting plasma physics.
While perhaps not quite as strong as the companion volume, this one is still well worth while. There's an excellent mystery by Paul Chafe, as well as good tales from Eric Flint & Dave Freer, James p. Hogan, and Gregory Benford. I wish that Baen has continued the series.