Okay, one series I read when I was younger. I don't remember if this was the official name and I can't remember the name of the author, but I believe it was called the Gap series. It was real nitty-gritty stuff, almost absurdly so at points. Aside from the local version of FTL (the eponymous Gap Drive) I remember it as rather hard sci-fi at points; artificial gravity is produced by spinning, and in more intense sequences there's a lot of attention paid to the stress of g-forces on ships and crew. The main characters were a couple of rival space pirates, a human navy crew-woman who got caught between the two, and a military administrator back on Earth.
When I say it was nitty-gritty, I mean it; profanity everywhere, loads of violence, sadistic scenes, quite a few rapes, aliens that specialize in body horror, you get the picture. Kinda amazed that my parents let me read it, heh. Also the plot was full of xanatos gambits and subterfuge and fake-outs, to the point where even in some characters' own minds you couldn't tell what they were planning or what their true loyalties were. I never did finish it, and now that the books are either in storage or lost over the years I probably never will.