The former seems to be a report on The Fair Folk of the British Isles, primarily. The author, a curious American, did a lot of information gathering at ground-level, so to speak: he traveled the countryside and talked to people.
"I have set forth in the first section in detail and as clearly as possible the testimony communicated to me by living Celts who either believe in fairies, or else say that they have seen fairies; and throughout other sections I have preferred to draw as much as possible of the material from men and women rather than from books. Books too often are written out of other books. [...] For us it is much less important to know what scholars think of fairies than to know what the Celtic people think of fairies. This is especially true in considering the Fairy-Faith as it exists now." -- Introduction, Section IV
I like this guy.
The second, which I have only flipped through, appears to be a summary of ceremonial magic, alchemy, and Kabbalah (The Kaballah?), with a dose of history and the author's own techniques. This paperback printing is faithful to the original, so all the Ss look like italic fs, which makes the words have a kind of lisp in my head. Though it may be dated, it looks fascinating.
I have a Pagan Blog Project post coalescing in my mind on my personal definition of deity. These books may give me more ideas, or at least better ways to word them.