The obvious answer to what to read before creating a campaign for people to really involve themselves in and get stuck into would be – science fiction, fantasy, something “related”.
I really disagree.
I think the best genre to set up your own mind for the campaign is murder mystery, and specifically Agatha Christie.
1. Agatha Christie solves the problem of how to involve random people into adventures in a lot of her novels, particularly the non-Poirot / Marple ones. The stock pulp heroes and heroines she uses are “Dick and Jane” types who are drawn in through a single large coincidence or plucky normal people who have some odd event strike them out of the blue. If you assemble ten or so of these hooks, you have very memorable introductions to use.
2. Agatha Christie starts with observations of people- her hero(ine) sits there annoyed at a fellow traveller on the same bus, or with a character being fired from a job for being rude to the boss, or having just demobbed after a war, or home on leave whilst injured – or penniless after their father dies. These origins are instantly engaging and interesting.
3. Her villains range from the painfully predictable to the truly depraved, but she gets some essentials so right so often- criminals are not as clever as they think they are, they are selfish, and they like to hear themselves talk if they are psychotics. On the other hand people who do something for economic or personal reasons keep quiet. She also uses a good idea a few times- the real crime (or quest) is disguised by the murder (theft, vandalisation, threat) of someone not connected. That way, trying to solve what the victims have in common can never work.
4. Love affairs. She is always sensitive to the fact that people fall in love when thrust together on an adventure- but they don’t always end up with the one they initially fall for! Especially when that person is actually the villain!
The Secret of Chimneys
The Moving Finger
The Pale Horse
And Then There Were None