Learning Router concepts

hello all,
If two routers are adjecent in an Internet say R1 with
192.168.1.10 and R2 with 192.168.2.10 (using Private IP'S instead Real
to specify my query) then both require to have each others entry in
routing tables?
That mean can i say if i see 5 Gateway IP addresses in Linux
Router R1 Routing table then they must be adjecent to PC1 Right? Does
Routers in Internet have Staic IP addresses? Where can i find
resources about Internet Routers?


kernel.lover