"Eon" by Greg Bear (1985)
"The glob dropped and fleshed out like a vampire in an old horror movie to form a masculine body, clothed in loose white shirt and forest-green pants. The figure seemed to solidify."
Greg Bear is highly regarded among certain aficionados of "hard sci-fi." He's written dozens of books, and his bibliography stretches back to the late 70s. This novel, Eon, is the first of four books in his "The Way" series.
In the early 2000s, a massive object called The Stone appears near the Earth. Several teams of scientists investigate this object, and after many years they uncover both the startling secret of The Stone's origin and its connections to worlds (and realities) far beyond their wildest imaginings.
In tone the earliest chapters of Eon reminded me a lot of Larry Niven's Ringworld, in that a cast of decidedly "diverse" individuals study of an object that defies our present understanding of physics, only to discover that a shadowy race of "engineers" is lurking behind the scenes. You could also compare Eon to Arthur C. Clarke's 2001 series, which also features a mysterious object(s) lying at the edge of our exploratory capacity, followed by revelations concerning its creators and their "message from the stars."
Yet I think Ringworld is the more apt comparison, given that Eon shares the same flaws. Despite the "hard science" on display, both novels fail to adequately think through the implications of the ideas presented, and instead attempt to overwhelm our critical instincts with concepts that were cutting-edge at the time. Both books also feature paper-thin characterizations, and tend to wander more than they ought to. The chief difference being that Ringworld is much shorter, and as a result much more readable.
I wanted very much to like Eon - I'd heard great things about it - but I found it less brilliant that its reputation would suggest. I felt like there were glimmers of better novels in its pages, but the whole was much less than the individual parts.
P.S. It may be that I'm being overly hard on this one. After reading Greg Egan's Permutation City, Eon might be a victim of my newer, higher expectations. Whatever the case, Eon definitely ISN'T in the same league as Egan's book.