The shamanic tradition is one version of spiritual philosophy that incorporates core practices in many spiritual practices around the world. No one culture has the sole claim to shamanism, and nearly every native culture of the world has touched upon the core shamanic beliefs at one time or another.
This section includes theories of shamanism that relate to multiplicity, such as the shamanic mask, totemic possession, the otherworlds as they might relate to internal landscapes, soul loss and soul retrieval, etc.
The Way of the Shaman by Michael Harner was very useful to me - keeping in mind that all the things said at this Amazon URL are quite true.
It's a basic technique book, does NOT particularly emphasize that you can get your ass handed to you in a shamanic reality, and is a simplified - but highly accurate - basic introduction.
And being taken out of cultural context - well that's actually a good thing. You need to put the techniques into yours. Aside from the obvious point - the techniques vary little from culture to culture, which argues strongly for their validity.