Yep, I've read it and have it listed as an essential source. I'm glad to see it's back in print. There are some obvious differences since his creatures live on the rim of a disk, so have the concept of "up" and "down" and one version of sideways, and gravity does make some gadgets a LOT easier to build, but even so I had to resist the temptation to nick lots of technology from it. So about the only gadgets I describe are cannon (you have to run the fuse down the barrel, of course, which does tend to cause a few problems) and a system for a group of soldiers to ford a river using two strong isosceles and a length of rope: