The Gateways TNG book is the only crossover book that really has any relevancy to any of the DS9 relaunch books, and merely explains how a big event introduced in the novel comes about and is then resolved. Other than that, the DS9 relaunch is very much standalone.No, I meant because lots of the stories cross over, Like TNG novels will have DS9 story Arcs cross over into them and it's hard to know which ones are required reading and which are not.