One of my primary questions going into this book was, "What exactly is a demon?"
Bane's definition of demon appears to be "anything anyone has ever called a demon". Fallen angels, pagan gods, Japanese youkai, goetic demons and various mythological figures all make appearances. The Encyclopedia of Demons in World Religions and cultures has thousands of entries that span several different cultures.
Entries include the name (and variations) of the demon and some mention of where it comes from (its culture, religion, grimoire, et cetera). Where possible, physical descriptions of the demon, and information on its behavior are also included. Some demons, especially those from goetic grimoires, also have information on what they might be summoned for or how they interact with people. Unfortunately, there are no pictures or illustrations.
Each entry is individually sourced (often including the relevant page numbers), which I really liked. I'm not very familiar with demons and demonology, and so I can't say with any authority how accurate these entries are. I can, however, check the sources given, both in the entries and in the extensive bibliography.
I wouldn't suggest this book as the only reference one would need (I'd be hesitant to suggest any single book for that), but I do think it's a good place to start. It's very helpful if you need to get a brief overview of a demon, and an idea of where to look for further research.
Note: I received a free copy of this book through the LibraryThing Early Reviewers program. This has no bearing on the content of my review.

A great reference book for all things daemonic. I teach classes that address monsters and supernatural beings around the world and throughout history. I now refer my students to this invaluable text when they need to do research.

A great reference for those interested in such things. Just yesterday I was reading a novel and came across a name that I was able to look up and get satisfactory information about. There are two things in particular I like about this book -- the straightforward writing and the sources added to each entry. There's also a lengthy bibliography, which I always enjoy. One criticism, however, is that this reads more like a dictionary than an encyclopedia. The author was deliberately brief in order to cover a large number of entries, so each entry is concise and introductory. Still, this will be a useful addition to my reference materials. Just remember, though, that this book is a first stop in research, not the last. ( )

Theresa Bane's _Encyclopedia of Demons in World Religions and Cultures_ is a more than adequate introductory text on the subject of world demonology. Bane presents in the introduction her conception of "demon", and despite using the Latin "daemon" for the Greek "daimon," is very useful in understanding how she presents the various spirits in the "Encyclopedia." This is important as many of the spirits, especially those from non Abrahamically influenced cultures, do not always fit Western culture's various understandings of the term. The book also boasts, and delivers on, a lengthy bibliography. While the "Encyclopedia" is heavy on Abrahamic and grimoire-derived demons, it includes spirits from a host of other cultures as well. Perhaps its greatest flaw is that it calls itself an encyclopedia when it is at best a dictionary.

An Early Reviewer win.
This is an excellent book with a huge bibliography and many sources. And while I sat down and read it through beginning to end, as a reference book, that's not the best way to look at it/use it.
It did, however, have the added benefit of keeping some people from sitting next to me on the bus.
I've also become entirely intrigued by Bensozia thanks to this book. I'm going to have to read Ecstasies by Carlo Ginsburg and reread Montaillou by LaDurie because I discovered she's mentioned in those books as well. (I hadn't recalled her in Montaillou, but I read that nearly 30 years ago.)
I discovered there are numerous demons of migraines, which doesn't shock me, and a demon of Morris dancing, which sent me into a laughing fit (I used to be a Morris dancer).
I had never heard about an association of Eostre with Lilith. I simply can't comprehend that one. Eostre was a Germanic pagan goddess who later gave her name to the holiday Easter. Unless the demonic association is simply because she's a pagan goddess, I can't see how the two would be related. Granted, I didn't go through the bibliography to look for a source because it's so huge. And I don't believe the author created this idea herself--I'm sure the documentation is there. It just struck me as strange.
The only quibbles I had with this book are things most readers wouldn't even notice. It was just weird things that happened in the styling of the book that I notice simply because I can't leave my job behind when I read a book (I'm a production editor, so I look for those kind of things to make sure they don't happen).
If you need a research/reference books on demons from not just one religion but many, this is definitely the book for you. ( )

Interesting concept. This book is great for someone that just wants to look up a demon and get a snippet about it. It's not something one just sits down and reads through. It might be helpful if you're reading something else that mentions a demon and you want a little more information. I was hoping for more correllation between demons and religions. As another reviewer mentioned: one culture's god is another's demon. ( )

Not a bad attempt at an encyclopedia of demons however I was hoping for more information on the demons. She used a bit too broad based on a definition of demon for my taste. I would have liked a bit more story behind each one. For a brief overview it is certainly comprehensive and extensive. In short this is useful if you just want a quick idea about a demon but not depth. I would also have enjoyed a few illustrations to help identify each one. Not one I would sit down and read through. ( )

As far as I can judge this work is a fairly comprehensive list of demons and other evil entities from various world mythologies and belief systems. The entries range from such princes of evil as Satan himself to minor demons such as Belian, who tempts children to talk during mass. Most entries list alternate names, country or relgion of origin, description of the appearance and of the types of harm the demon specializes in. Some entries also contain information about how to avoid or defeat the demon. Each entry ends with a list of sources.

The bibliography is extensive, with over a thousand entries. The book is also indexed and has an introduction which gives a general summary of the idea of demons.

Since the main body of the work is alphabetic it would have been helpful to have secondary lists by nation or culture, such as all Chinese demons, all African demons, etc.

I'm not sure how useful this book will be to the average reader; it certainly isn't the sort of work one reads straight through. And given the author's background in vampire studies it is perhaps not surprising that many of the demons listed seem to be vampiric in nature. ( )

This is a very cool book. The only thing that could make it better is a lot of color illustrations (sadly, there are no illustrations in the book at all). Very thorough, very well researched, very interesting. ( )

I was very much looking forward to getting the book “Encyclopedia of Demons in World Religions and Cultures” by Theresa Bane. I had never heard of the author, but am quite interested in the theology and history of demons. It took a few moments in the Preface to turn my hopes away. Ms Bane is a vampirologist, a mythologist who specializes in cross-cultural vampire studies. In those studies she discovered some vampiric entities also described as demons and got interested. Not a bad start if she studied demons thoroughly. She does not appear to have done so. Although she has notation of source for each snippet of “demon” information, the full bibliography, and index which are requirements for academic work, the sources she used show how little she understands the topic. She considered Jacob Sprenger (author of Hammer of the Witches in 1487); Helena Petrovna Blavatsky and other 19th and 20th century mystics; and scholars in other topics, such as linguistics and theologians whose only connection to demons was their mention of vampires; to be scholars of Demonology.

Her definition of demons is broad enough to accept these vague sources as valid. “According to their original mythologies, these ... demons were said to have been created in a hell-like dimension or were described as being agents of evil who worked directly against the best interests of humanity.” Sorry Ms. Bane, I can label some politicians with this definition.

In her attempt to list every god, goddess, ghost or spirit who might be considered a demon by anybody she made a long list of “demons” with not enough space to write anything about them. Therefore we do not hear that this name was god to one people and therefore was considered a demon by that people's enemies. We do not get any feeling for what these so-called demons were within their own culture. Did I mention that she misinterprets, misquotes, and makes things up? She has made a fascinating subject both frustrating and boring. I do not expect to be bored while trying to learn about something as fascinating as what different cultures considered to be evil. I was. Bored, that is. ( )