I found, online, a scan of Malinowksi's well-known essay on the topic. It think this sort of thing can be quite useful to fantasy writers and world-builders, in that it gives an anthropological view of these subjects. I recommend skipping the introduction and going straight to the essay under the heading Magic, Science, and Religion.
Magic, Science and Religion and other essays by Bronislaw Malinowski
Magic, Science and Religion and other essays by Bronislaw Malinowski