A sequel to fourth season's "For the Cause", this Sisko episode explores the ideas obsession and stubbornness, turning him into a combination of Ahab from Moby Dick and (as acknowledged in the episode) Javert from Les Miserables. It's a personality that suits Sisko, with Eddington's arrogance and smugness ensuring that the audience's sympathies stay with the Captain.
Most of the episode takes place on the Defiant, with the writers throwing in a couple of wrinkles on board. First, a 3D "holocommunicator" takes the place of the viewscreen, which allows Kenneth Marshall ("Eddington") to interact with Sisko on the ship as opposed to through a TV screen. (It's not a piece of technology that's suitable for regular use; it requires careful exposition to avoid confusing the audience, and that's not something you want to have to do every episode. But it's nicely done here) And second, damage to the Defiant leads the crew to operate the ship manually, complete with someone (Nog) having to relay messages between the bridge and engineering. The two ideas work in concert with each other to create an electric environment which is all the more special for not overstaying its welcome, rarely appearing again in any incarnation of Star Trek.
Eddington himself does return to the series; coming back later in the season for "Blaze of Glory" And the success of "For the Uniform" leads the writers to go dark again and push the envelope even further in sixth season's "In the Pale Moonlight" - and even better episode.