It covers a lot of ground - all the major occult, esoteric and mystical conditions in European and American history. And it has an interesting thesis - that esotericism and mysticism are simply two related paths towards gnosis; the 'via positivia' and the 'via negativa.'

But what it has in breadth is lacks in depth. It doesn't fully explain any of the movements or thinkers, and often lacks even the most basic description. Many of the chapters are little more than a bibliography and don't actually mention what the movement was or what the thinkers thought. You learn the names and dates of Rosicrucians, but you never find out what a Rosicrucian is. ( )