I loved this book and read through it quickly, as it has everything I have come to know and love from this author. It is perhaps not his best book ever, but it really is a very good read, and this series is as good a place to start reading O. S. Card as any other book he has written. Thus five stars, although maybe only just!
So here is some detail: Ruins picks up where Pathfinder left off, with Rigg and his companions having crossed the wall into a whole new wallfold. The wallfolds keep seperately developing colonies apart, and it becomes apparent that each of the original 19 colonies on the planet Garden took some very different lines of development, and the author's imagination shows through clearly as we are introduced to ideas of just how differently they could develop over 11,000 years of history.
The plot moves on significantly in this book, and Rigg and his companions will truly discover their place in the world - why they are here and what they must do. I thought the plot development was very good.
I noted with Pathfinder that Card apeared to be recycling and re-using ideas from his earlier books and short stories, and this book seems to have done that moreso. It is as though card has taken a whole set of his best ideas and tried to entwine them into a new masterpiece - a book that he could never have written until he had written others such as "Pastwatch", "Hot Sleep" and "The Worthing Chronicles", "Ender's Game" and "Xenocide", and even other less well known books such as "Wyrms". The time twisting storyline is clearly found in "Pastwatch" with Card's clever concept of the conservation of causality. However, despite all the development he has applied since Pastwatch, I feel at this point that Pastwatch was the better story.
There were places where this book got so complex that it was as if the author was himself confused.
Whilst trying to avoid spoilers, I would say one of these was a time when the travellers approach a new location to find themselves greeted by a large group of happy people - several thousand of them "including babies" we are told. So the time travellers go back in time a couple of weeks to avoid the welcoming committee and are instead greeted by two less friendly people.
What makes no sense is it becomes apparent that, whenever they had arrived, the plan was to greet them with just the two people - so why were the thousands there? Moreover there should not have been babies (or at least not more than one baby) amongst the greeters.
This part of the story simply made no sense and it is as if the writer wrote the one scene, then put the manuscript away and came back some time later and kept writing, without noticing the discrepancy. Maybe the discrepancy has some later story element that will become clear in book 3 - but it shouldn't have, because that future should now not exist. It ended up just being confusing.
Another example near the end of the book, Rigg goes back in time to prevent himself doing something that he regretted. But Card gets it wrong here - Rigg goes back to an event in his past that should no longer exist because he had already gone further back and changed that future. Conservation of causality was broken on that one.
I suspect it is all but impossible to write completely consistent time travel adventures. One of the reasons I valued Pastwatch was that there was a story that did seem internally consistent. All the same this one was good despite the occasional discrepancies.
Ruins has all the stuff that makes card such an enjoyable writer. Plenty to chew on, plenty happening, some unexpected twists and some clever ideas. Despite any problems, I highly recommend this series and this book.