Richard Thompson is one of the finest songwriters of his generation. Four decades and more than two dozen albums into his career, the 58-year-old British guitarist remains as creative — and surprisingly little known — as ever. With his ex-wife Linda, Mr. Thompson released six astonishing albums during the 1970s and early ’80s, but the musical and romantic partnership famously ended in 1982 with a masterpiece, “Shoot Out the Lights.” Linda lost her voice, but Richard kept turning out the songs, moving from all-acoustic outings to live albums to electric music over a span of 32 albums. For his recent project, he was hired by Werner Herzog to compose the music to the 2005 documentary “Grizzly Man.”

“Sweet Warrior” (Shout Factory) is unmistakably Richard Thompson in its merging traditional of folk themes like love, death, and heartache with rollicking, dense rock arrangements, which here include horns and strings. Mr. Thompson has a rare ability to pen lyrics as emotionally and intellectually complex as his music, and into each word he imparts a characteristic skepticism and bitterness.

Mr. Thompson, who got his start in the late 1960s as a founding member of the British folk rock group Fairport Convention, prefers to navigate tradition and innovation from one song to the next on “Sweet Warrior.” The album has more blues twang and reggae chop than pastoral lilt. A country-rock grimace drives the Iraq war death chant, “Dad’s Gonna Kill Me.” Between lines like “at least we’re winning on the Fox evening news” and “I’m dead meat in my Humvee Frankenstein,” Mr. Thompson repeats “nobody loves me here.” The “Dad” of the refrain is Baghdad itself, where “nobody’s dying if you speak double-speak.”

But Mr. Thompson can be as powerful on those quiet songs as he is on the rowdier ones. On “Take Care the Road You Choose,” he delivers a confessional of lost love that warns against passing time and connections strained, and becomes something far bleaker by the final note. The lyrics are potent: “If I had been in my right mind / Not looking for ghosts behind me / Then I’d hold you with my fingers burning / Kiss away your little tears of yearning.”

As befits the genre’s darkness, Mr. Thompson’s delivery gets more poker-faced as it nears the bloody drama. When the singer realizes his love won’t be had in this life, he sings, “If I ever get out of my mind / Guillotine myself to stop me dreaming.” Similar is the grief-filled “Poppy-Red,” with the line, “There in a field, warm and red as the blood she shed.”

For all the pain and resentment in his songs, Mr. Thompson has always maintained a sharp sense of humor. “Mr. Stupid” is the fantasy of why a man can’t “say what’s on my mind, dear” because “the judge will slap me down.” In the end, after recounting what would happen if he did, his “alter ego’s ready for any questions.” Recently, Mr. Thompson amused fans with his cover of Britney Spears’s “Oops, I Did It Again,” confirming himself as a tireless popular music enthusiast and someone willing to make fun of himself as he grows older. He has long proven himself to be someone who can do just about anything. Thankfully he sticks to what he does best.

Mr. Thompson will perform on June 21 as part of the Celebrate Brooklyn arts festival.