The front cover photograph of Johnny Cash’s American V is striking.

Where the previous four American recordings sported iconic cover shots of Cash, weathered but still rugged and ready to take on all comers, American V depicts a stunningly frail Johnny, seated and hunched over, recording his vocals for this penultimate album. The picture was taken in between June Carter Cash’s death in May 2003 and Johnny’s passing in September of that year, and the man’s heartsickness is, amazingly, visible.

Unfortunately, there’s no way of knowing whether Cash would have wanted this photo published, or the recordings it accompanies released. American V, subtitled A Hundred Highways, is the first of two planned posthumous releases from the Man in Black’s final sessions with Rick Rubin, a partnership that resulted in one of the most incredible late-career renaissances I’ve ever seen. Rubin’s love and respect for Cash is evident and obvious throughout the four previous American albums, and in the box set Unearthed, released just after Cash’s death.

And it’s that very love and respect that one has to trust when listening to American V, one of the most fragile and intimate albums in Cash’s discography. Rubin brought something amazing out of Cash in his final years – the man was always one of the best and most important singers and songwriters ever to grace the earth, but by the early ‘90s, he’d lost his way. The American series is perfect and poignant, an aging Johnny Cash finding his footing as an interpreter of all kinds of songs, produced with respect and reverence.

But we’ll never know what the man himself would have thought of this album, finished years after his death. The vocal tracks for this record (and its successor, American VI, rumored to be released this year) were recorded between May and September, 2003, but the instruments were added later, and the sequence was drafted by Rubin. Who knows if this is what Johnny would have wanted for his final statement.

If you can handle the implications of this (or of any posthumous release, for that matter), then you’re in for a rare treat. This is a snapshot of a heartbroken, yet hopeful Johnny Cash, a once-mighty man felled low by the loss of his one great love. The Cash on American V is fragile and shaky, his voice still commanding, yet somehow weaker. The arrangements are subtle and graceful here, never stealing focus from That Voice, which once moved mountains, and now sounds so oddly small.

American V opens with Larry Gatlin’s “Help Me,” and its withered plea for God’s grace is a stunning choice for a leadoff track. That it’s followed immediately by a whip-smart version of the old traditional “God’s Gonna Cut You Down” is an ironic touch, one Cash might have liked. That’s followed up by what Rubin says is the last song Cash ever wrote, “Like the 309,” a meditation on death and trains. These three songs set the tone brilliantly – American V is concerned almost exclusively with death and God.

Even the love songs here are mournful, and one imagines that they were chosen because they reminded Johnny of June. One of the album’s most emotional moments, believe it or not, is Cash’s read of Gordon Lightfoot’s “If You Could Read My Mind.” Like a lot of the American series, which found Cash covering the likes of Soundgarden and Danzig, it shouldn’t work, but it does. Here Cash’s voice is at its weakest, choked and wavery, and it’s impossibly sad to hear him struggling with both the melody and his own loss. I’ve never considered how heartbreaking the song is: “And you won’t read that book again because the ending’s just too hard to take…”

Even sadder is “Rose of My Heart,” Hugh Moffat’s country classic, which in other contexts is a wispy trifle, but in this one is an outpouring of love and devotion. I don’t know how to say this so that you’ll understand without hearing it – listening to this song, and Johnny’s shaky yet strong delivery of it, you can literally hear how much he misses June.

Theirs was a love so strong that he couldn’t wait more than four months to see her again, and the songs of death here are little victories, small rejoices. The album ends with “I’m Free From the Chain Gang Now,” which Cash turned into a hit in 1962. He revisits the song as a sweet acoustic hymn, and though the metaphor is obvious – the prison is his body, and this earth, and his death will set him free – it’s also astonishingly powerful.

American V is not a fun listen, and not for those who just saw Walk the Line and want to check out Cash’s work. It’s a difficult album, because it’s so intimate, so unflinching – here is an aging Johnny Cash, a man who once seemed immortal, and by God, he sounds old here. These are the songs Cash chose to mark his final days, and there’s nothing here that isn’t made more significant in that context. Even Bruce Springsteen’s “Further On Up the Road” becomes a song about death, and about meeting June again on the other side.

But perhaps the centerpiece of the album is Rod McKuen’s “Love’s Been Good to Me,” because of its upfront intention – the song is a summation of life, sung from the point of view of an old man looking back. The best things in his life, he concludes, are the times when he’s been loved. Sounds trite, right? Just listen to Johnny Cash, age 71, sing this little tune, and imagine what he must be thinking as he sings it. It’s just devastating, yet wonderful.

There will be one more in the American series, and then that will be it. Johnny Cash, a figure so imposing that at times it seemed he was music personified, will be gone. But American V (and presumably American VI) is not some cash-in, pardon the expression. It is a lovingly assembled, beautiful and heartfelt tribute to the man, and a revealing glimpse at how he lived his final months. In many ways, it’s the best of the American series, because there’s no time for experiments or whimsy. This is a last will and testament, and every moment counts.

I started this review by casting aspersions on Rick Rubin, so I wanted to end it by thanking him, endlessly, for seeing how important Johnny Cash was to music and rescuing him in the last years of his life. Johnny got to go out on top, with the critical and popular acclaim he enjoyed in his early days, and along the way, he got to make some of the best records of his life. The American series is a monument, a great capper to an amazing career, and there’s no doubt that it wouldn’t have happened if Cash hadn’t found Rubin.

As I said, there’s one left, so it’s too early to sum up my feelings about the series yet. But American V is a heartbreaker, a lovely piece of work all on its own, and if this were it, then it would be as grand a final album as I could hope.

Next week, a dozen possibilities. But probably Muse. Or Sufjan Stevens. Or the Lost Dogs.

See you in line Tuesday morning.