is a terrible, hideous travesty of a book, and should never have been written.
Wait. Let me back up and start at the beginning. In 1975, Joe Haldeman published a seminal novel, The Forever War. His extrapolation of Vietnam into a Heinleinesque future won a well deserved Hugo. I highly recommend you read the review (and the book, if possible) before continuing, to truly grasp how bad this book really is. Then, in 1997 he published a somewhat flawed not-sequel called Forever Peace.
In 1999, he published the true sequel to The Forever War, picking up the story of William and Marygay Mandella, living on a wintery "DNA preserve" planet, under the aegis of Man, the cloned, self-telepathic human society. After a while, a group of veterans decide to take another one-way trip into the future, a 40,000 year jaunt to see if anything changes. They are denied permission, hijack the ship, and go anyway, along with one Man and one Tauran, the enemy-cum-ally they once fought. Good enough, sofar, as you're now halfway into the book.
Eschewing the collapsar jumps that knocked them centuries out of their own time during the war, they point the ship due Galactic north and settle in for a twenty five year trip. Almost immediately, things start to go wrong. At first it looked to me like an H-bar problem, quantum tunnelling on a macroscopic scale. Soon, their entire stock of antimatter propellant vanishes, sublimed away into nothingness. They load up the lifeboats and head back. Still doing OK, the possibility of an interesting mystery.
When they get back, all the people are gone, nothing but piles of clothes as if everyone in the world has suddenly vanished where they stand. The Tauran and the Man are both unable to contact their counterparts in the universe. Shortly thereafter, the group splits, sending a few (including the Mandellas) to Earth to see what's happened. And this, my friends, is where the massive suckitude begins. The last few chapters.
On an empty Earth, the group meets a representative of another type of life, immortal with physics-defying abilities, who supposedly have been living among men undetected for all of history. But they don't have any idea what happened either. In a dreadful deus ex machina, a node of God hirself appears, claims that the ship got hir "attention" by attempting to leave the galaxy, and the experiment known as the Milky Way is over. Mandella convinces this supreme overpower that it shouldn't kill everyone, where it reveals that all the people are simply in cold storage in out-of-the-way places on all the inhabited planets. God then restores everyone, changes a couple "minor" laws (c is 5% slower, pi now equals 3) and everyone lives happily ever after. There is absolutely nothing in the first half of the book to rationalize this, except for about three lines of Tauran pseudomysticism that seems to have been added after the ending was written.
I warned you. Haldeman would have been better off to just put it down when he got stuck and forgotten the whole idea. The editor who passed this piece of dreck should not be allowed to approve science fiction as they obviously wouldn't know it if it bit them on the ass. I have rarely been so dissapointed in an author. Haldeman set the bar very high for his contemporaries in the 70's, but couldn't be bothered to ever try to clear it himself.
Rating, on the eponymous sliding scale: No stars, downvote, nuke with 50XP loss. I'd put this in the category of Node You Bookcase, except I wouldn't own a copy of it if it was a personally inscribed signed first edition -- I'd razor out the signed page and recycle the rest into Chick Tracts. It's that bad, folks.