My manual for GalCiv is JavaScout's website, a truly awesome bit of work. After you run down the links enough you'll have them cached on your drive and then you can access them while working offline. Is it as good as a 300 page textbook-sized manual would be? In some ways no, in some ways its better, as JavaScout updates his page with each patch whereas a manual never does.
If big manuals are a must for you in gaming then be prepared to stop gaming, because only the largest companies can afford the reduced profit they get by making and including a large manual. And even the biggest companies are shipping games now with no more than booklets.
If you don't have a decent online capability, then you need to drop PC gaming and switch to consoles, because the online community is where the patches, bug fixes, workarounds, mods, and other goodies are at. If you pay by the minute for your internet connection then you either need to be able to afford it or just move to another type of gaming.