I have read the first trilogy in C.J. Cherryh's Foreigner universe and found them to be excellent. It's been a while, though, so I'm re-reading them.
I've also discovered that there are actually four trilogies, with a fifth currently in progress. I've also learned that the timelines for each trilogy overlap, although the story arc for each trilogy stands on its own.
Is there a "canonical" order for reading these? Is simply reading them in the published order the best way to do it, or will I get more out of them by reading them in an alternative order? (For instance: "read book 1 of trilogy 3 before reading book 3 of trilogy 2.")