Leviathan Wakes

Is this Space Opera? Is this a Murder Mystery? Yes. Yes. It has the best of both of these. This is the best space opera since David Weber's Honor Harrington series lost my interest. Smooth formula of a Murder Mystery. It blends these two genres was well as Firefly blended Space Opera and Western on TV.
The setting is entirely within our solar system and there are no aliens. Some may say this disqualifies it from being Space Opera, but the setting is such that the size and scope matter. Earth, Mars and the Belt are three distinct factions fighting for control or independence. Humans are on the verge or launching a generation ship to fly to the stars. They have a sub-light speed drive, but no faster than light travel. Travel between planets and asteroids takes time and impacts the characters.
Miller is a believable as the over the hill cop with an unbending moral compass. He's fired from his job working security in Ceres after refusing to drop a nonsense case that was only given to him because he way viewed as inept. Investigating the murder of an Earth heiress turned Belt rebel, Julie, he meets up and joins the crew of Holden.
Holden is the captain of a crew of four survivors from the ship that investigates the destruction / sabotage of the ship Julie was on. Holden is the honorable XO that is thrust into the roles of Captain when most of the crew is killed off. His strong belief system clashes with Miller, but they have the grudging respect that comes with people that have different outlooks on life, but respect each other for it.
Like a lot of murder mysteries, the murder isn't as simples as it seems. There are a lot of fast starts and misdirection that keep the reader guessing. This reads a lot like hard science fiction, without having the hard science descriptions in it.
The real story is the compelling character interaction. There aren't any throwaway characters. The deaths matter. The red herrings matter. If you can follow through the various twists and turns the climax is very rewarding.
This doesn't read like the first in a series. It's a well fleshed out world and has a very satisfying conclusion. It will be interesting to see where this series goes in the future. I know the author has a second book in the series and a short story that details one of the shaping events of the first novel.
Note on this version: This version contains two full novels. Both of which are the first book in series by the same author. I didn't know this when I read it. This impacted my reading of the book quite a bit because the climax came about half way into the book, so took me a bit by surprise.