I have long ago become a fan of Kristine Williams's writing. I have read "When the stars walk backwards" and its sequel at least two times because I loved the characters so much. For some reason I never got around to also read the Keeper series and have now remedied that mistake. It's a wonderful read for anyone into sci-fi and the theme friendship which is masterfully explored in all its dimensions throughout the series. Kristine has a great way of writing that advances the stories quickly and fast-paced mostly through dialog and "show" not "tell". Her characters are fully 3-dimensional and loveable even though or maybe because they each have their quirks. If you like this book you should not stop here but continue on with the other 3 books in the series ("Madness", "Tools of Extinction" and "Sha'erah").