Jack, Merle, and Loaf have been planet-hopping across the galaxy ever since they discovered the Server. It looks like a laptop, but has power beyond any computer system on Earth. And of course, there are a slew of bad guys who want to steal it to capture its power. Jack and his friends are battling to keep the Server safe. But this little machine holds another big surprise. Not only does the Server have the power to teleport people from place to place, it can actually transport our heroes through time. And time travel opens up a whole new galaxy of possibilities...
This is in my opinion the most crucial book. If you do not read this book all the other books don't make sense. With the knowledge that Tiresias downloaded before it died they travel in time to when there was no Outernet.