A plea for Clare: fiction and non-fiction on religious cults and evangelism

Clare's interested in a recommended reading list on the topic of religious cults and evangelism.

I can think of some mentions in stuff like Pynchon's Vineland and Alison Lurie's "Imaginary Friends" seems relevant.

There is a bit of info from this site which has done a study on the topic (and yes it does seem there is as much fiction on this as anything advisory/non-fiction).

Anyone else got any ideas? Am sure Clare would appreciate some offers...