Do not copy the entire game model to the server, you wouldn't like to load all the textures and detailed meshes on your server. Keep it as simple as possible, handle all the important processes like the location, health, any movement but do not load everything. - NEVER TRUST THE CLIENT.
There are many books, along with multiple wiki's. Every engine supplier like IdeaFrabrik, Epic Games, Exitgames, Unity (also supports mmo's) has very good documentation for their productproducts. Most of that stuff is public so you got access to complete solutions and you can actually find out how stuff works.
The easiest way to find a book you need is to search Amazon for MMORPG, then go to the book category and choose the "programming" sub category. If you google it you will get unwanted results...
I haven't gone deeply into server programming, but as the matter of fact, I was close to choosing the Unity+Photon Cloud engine solution for my MMORPG project. (HeroEngine won) The server side is done in this one in C# and one thing I strongly remember is the way things were explained in the tutorials.