As a student of Slavic myth, I had been champing at the bit to get hold of this volume, hard-to-find but one of the few in-depth English resources on the subject. While the tome is certainly weighty enough to make all your academic dreams come true and is nicely laid-out in most respects, I was ultimately disappointed.
The subject matter seems to vary fairly widely in accuracy and scope; while appropriately slavish attention is paid to Russian folktales and folk figures such as Baba Yaga or Vasilisa the Wise, older Slavic myth and its deities seems to fall by the wayside some, leaving most Slavic gods in the dust with only a short, unilluminating paragraph before Dixon-Kennedy moves on. Some places clearly seem to not have even been edited, such as when the god Yarilo is described as a female "goddess" of springtime and eroticism but the rest of the paragraph discussing the deity appears to be referring to a male (for the record, I have never heard Yarilo/Jarilo referred to as female in any other source). The lack of discussion (or even acknowledgment) of controversial subjects also hurts the book's scholarly credibility, as when the entirely reconstructed and hotly debated god Belebog is not only included in his own entry but also discussed as if there were no question whatsoever regarding his existence or functions.
Dixon-Kennedy also includes a goodly amount of information on Finno-Ugric and Baltic mythology, which is often irritating as little of it has more than a vague linguistic connection to Slavic myth. It's great to note the parallels and cultural mixing between cultures, but when we're reading through entry after entry about Lapp deities that have nothing whatsoever to do with Slavic culture or myth, it becomes clear that the book is trying to do too much and would likely prove confusing for beginning students in the subject.
The book's general encyclopedia format is handy enough; the inclusion of a by-subject and by-culture topic index is a great idea, but the fact that it has no page numbers and requires you to flip back through looking for each individual entry prevents it from being as useful as it could have been. All in all, it's a decent beginning point but is too flawed and generalized to be much use to a serious student, and contains too much misleading or unsubstantiated material for me to feel entirely comfortable recommending it to a beginner.