The protagonist is an agent of a not-so-nice galactic empire run entirely by humans. The key technology is a sort of slow transporter, where an object (or human) is disassembled in one location, stored, and then reassembled at a later time and/or different location. Recordings can be edited to reassemble someone in a more youthful body or to modify a person for a different planet's environment. The computers that control this process are super intelligent, but programmed to be willing slaves to humanity. The protagonist is a troubleshooter of sorts, traveling between star systems to find and solve problems. He is a unique individual, no more than one copy of him ever exists in the galaxy. At one point in the novel, mention is made of the empire's judiciary, which is made up of replicated individuals; having the "same" person on each court ensures consistent decisions throughout time and space.
Per Alex K's answer, it sounds like you're describing the Altered Carbon series by Richard Morgan.
Slow transportation of bodies (by "needlecasting") is a major theme of the book and FTL travel is impossible. The description on wikipedia also suggests that the main character is some sort of multi-talented troubleshooter.
Kovacs is an ex Envoy, a military unit formed to cope with the challenge of interstellar warfare. Faster-than-light travel is only possible by subspace transmission, called needlecasting, of a digitally stored consciousness to "download centers" where resleeving into physical bodies can be carried out. Transmitting normal soldiers in this way would severely inhibit their effectiveness, since they would have to cope with a new body and an unknown environment while fighting. To combat this, Envoy training emphasises mental techniques necessary to survive in different bodies over physical strength, and the sleeve in which they are transmitted has special neuro-chemical sensors which amplify the power of the five senses, intuition and physical capabilities. The effectiveness of the Envoy Corps' training is such that Envoys are banned from holding governmental positions on most worlds. Kovacs is persistently wracked by his memories of the action taken by the Envoy Corps in a battle on the planet Sharya and especially by the military debacle on Innenin, in which the Corps suffered extensive casualties after their stacks were infected with a lethal virus, Rawling 4851.