Very tough call.
I'm going to have to go with Strikeforce. I think it has the best overall info on being a GM. From a step by step to building a campaign from an idea and developing it over time, to the character story, blue booking, pacing story arcs, and the player types (what different players want and need to have fun in their game). Overlaying this onto any genre and any system is likely to lead to a good time.
The Marklands runs a close second. So many ideas from there. As does the AD&D Dungeon Master's Design Kit, an excellent resource for helping to shape your ideas into playable adventures for your group, that keep the important elements, and throw out the superfluous stuff that won't add to the story, the play experience, etc.
I noticed that my top three and GM focused books.
As a player with no GM concerns, my first choice would probably be the 4th Edition Champions book. You could model just about any character you want with those rules. I might put 5E or 5ER in its place someday, but I don't have enough experience with it yet, so that's just speculation.
I'm going to have to go with Strikeforce. I think it has the best overall info on being a GM. From a step by step to building a campaign from an idea and developing it over time, to the character story, blue booking, pacing story arcs, and the player types (what different players want and need to have fun in their game). Overlaying this onto any genre and any system is likely to lead to a good time.
The Marklands runs a close second. So many ideas from there. As does the AD&D Dungeon Master's Design Kit, an excellent resource for helping to shape your ideas into playable adventures for your group, that keep the important elements, and throw out the superfluous stuff that won't add to the story, the play experience, etc.
I noticed that my top three and GM focused books.
As a player with no GM concerns, my first choice would probably be the 4th Edition Champions book. You could model just about any character you want with those rules. I might put 5E or 5ER in its place someday, but I don't have enough experience with it yet, so that's just speculation.