Ringworld's Children 
Ringworld's Children returns series protagonist Louis Wu to the titular world. Louis and his friend The Hindmost, an alien of the Pierson's puppeteer race, are prisoners of the Ghoul protector Tunesmith, a Ringworld native, who is deliberately provoking the warships that surround his world. All the star-faring races of Known Space have sent warships to the Ringworld, and they are already at the brink of war. If fighting breaks out, the near-indestructible Ringworld will be destroyed: dissolved by antimatter weapons.
The Ringworld series is so complex and ambitious that Ringworld's Children opens with a glossary and a cast of characters, inclusions that even many Known Space fans will need. Newcomers to Niven's artificial planet should start with Ringworld. --Cynthia Ward
Reviews
There are repeated jumps in time that are explained but are still so disorienting that they distract you from what is taking place as you read the book. Niven's usual detailed depiction of the alien or foreign is almost completely absent from this work, and the reader spends much of his or her time re-reading to try and figure out if they missed a page by accident.
The treatment of the primary personas in the book is almost offhandedly shabby.
Louis Wu, the longtime main hero of the series is swep along with the story rather than being the guide for the reader that he had been up until this book. He is constantly distracted by self doubt, lament over Teela Brown, and his desire to bone anyone he meets.
Chmee: Pretty much absent. His one appearance late in the book is exempt of flavor.
Hindmost: bleh. This one has been one-note since the first appearance. Typical Puppeteer "I'm scared! But I can be manipulated int doing scary stuff."
Chmee's son "Acolyte": starts out as an interesting persona in the first 1/3rd of the book, but becomes just a minor note lost in the confusion of the jumpled plotline.
Tunesmith (the Ghoul Protector): Banal. While he shows some potential to live up the the Brennan monster, the original sentient Protector from the novel "Protector", he ends up being not much more than a step ladder.
The new characters in this novel are:
Roxanny: An ARM agent, crashed on the surface of the ring. Dick-fodder for Wu, and other male characters. The dynamic between her and Wu has moments but they are never adequately explored.
Wembleth: A "native" of the ring. A plot-point involving this guy is one of the only interesting ones in the book, sadly it is explored and dropped in about two pages.
An actual Pak Protector: Who is so uninteresting that even though I finished the book last night I already forgot her name.
This book had so much potential, with the introduction of an original Pak I would have loved to learn more about them and the origins of the ring, but all of that is glossed over.
Fortunately the hardover was very cheap an I'm a Amazon Prime member so shipping was free.
Summary: Worth reading if you have read the previous three and can get it cheaply enough. Not a good intro to Niven, who is usually so much better than this.
Having now re-read the entire Ringworld series in succession, I can't agree with those who have so violently disliked "Throne" and "Children". Both books read very much like standard Niven work, and standard Niven work is several cuts above the average SF novel, so why all the complaining? This book was a page-turner for me and I enjoyed very much getting one more glimpse at this fantastic "playground of the mind" and the denizens who inhabit it.
Is this the end of the series? Niven seems to be angling that way. Though I think there are a lot of Ringworld stories that could still be told, even without Carlos Wu or Known Space being a part of the equation.
*** SPOILER ALERT! ***
My only real beef with this book is how Louis Wu's transformation into the Wu-monster turned out to be so anticlimactic. Such a life-altering experience should have profoundly affected the outlook and thoughts of Louis, but when he awakes after having consumed Tree-of-Life he seems only like a mildly-smarter version of himself. The accentuated hyper-intelligence of the Protector is not much in evidence, nor does Louis seem to experience any profound emotions regarding his unexpected transformation.
Of course, the instant Wu awoke as a Protector, I knew he'd use the super-autodoc to reverse-engineer himself back down to normal "breeder" capacity. This too should have been further expounded upon, psychologically and emotionally, but throughout it all, turning Protector and then back to breeder, Louis still reads and feels like the same old Louis. And while some fans might have found that comforting, I found it to be not very consistent, given the fact that Niven has spent most of his professional career hyping the Protector and how transforming into a Protector drastically alters the mind (and body) of a normal human being.
Now, if you're looking for an entertaining foray into one of the more interesting classic sci-fi universes, with strong characters, and several surprises (not eye opening revelations, just surprises), this book is for you. Niven introduces some interesting new characters, and doesn't waste time on old ones who's stories have been told. He uses his invented technologies as plot-advancing devices. The book has a pace and urgency that wasn't present in Throne, and a clearer exposition than previous sequels, especially during the fast paced moments. Given his tendencies, we won't know for a while whether Niven plans on adding to the Ringworld epic, but if not, this brings satisfying closure to the important characters and to the ringworld itself.
Nivin's writing, too, has changed over the last 35 years, which is hardly surprising, and his readers' tastes have undoubtedly changed, too. Larry has other, newer things to say today, and they're worth reading. You need not have read the previous three books, but might be a good idea; the Ringworld books tell a complex story, and if it's been a while since you've read them, it certainly wouldn't hurt to do a bit of review.
Larry updates his slant on technology, but he does it in a way that weaves it into the previous books. This may jar some readers, but it has, after all, been 35 years.
Recommended.
