I'm pagan, not Wiccan. I actually didn't realize this was mostly a Wiccan book when I got my hands on it. I possibly wouldn't have taken it and started to read it if I had known it was Wiccan. I'm not against Wicca or its practitioners, but I don't terribly care for the strict concepts of that belief system*.
The sections I liked most revolved around divination and herbal matters. I found that information to be very useful. I've read various other books about those subjects, but most of them have been disappointing in some way. These sections struck my interest and provided useful information.
Other sections involving things like the elements, Sabbats and Esbats, runes and that sort of thing provide about as much information as you could easily get for free by using a Google search. Granted, such a tool was not accessible in the time this book was originally published as it is now, so I'll give a bit of a pass on that, I guess. Still, you'd be better off doing a few Google searches or asking within the various witchcraft, paganism, and Wicca communities all over the internet, including Facebook, than to bother yourself with this cumbersome book!
Speaking of, this book is much too big. I understand that it was intended to be something of a workbook and not exactly a textbook, but it's still much too large. It makes it awkward to sit and read it and it stores poorly on a bookshelf due to its strange size and shape compared to every other book you'd ever see in a bookshop.
I've seen this book suggested quite often in beginner communities, and I am NOT one of those people who denounce younger people becoming somewhat suddenly interested in the Craft. I think that's good, not bad, and so the hatred aimed at the younger people interested in Wicca, witchcraft, paganism, and so on is horribly misplaced and downright idiotic. That said, I personally don't recommend this book for a beginner. Truth be told, I have yet to really find any written books that I'd positively suggest to a beginner. Regardless, this just isn't one of them.
If you're interested in this subject, there's no harm in reading this just to help yourself get a perspective on how different the belief structure can be from one person to another. I think in that way, it's a great tool to learn about how different every witch really is from the next one. No two are ever going to fully belief or practice in exactly the same way, so as a lesson in how different we all are from one another, THEN I suggest it. But if you're trying to find actual history or solid information about the Craft, this probably isn't a good place to start.
*This book is like many Wiccan reference books I've read in which the author says that his or her way is the ONLY way in which to conduct magick that will positively work. For example, you must always, always, always cast a Circle or that your candles must be a specific color and you must use very specific herbs or your Casting will completely fail. I don't agree with that one little bit. Consider our ancestors. Would they have had easy access to every single herb in existence? No, they lived in various places on the planet without online shopping available (or, hell, even indoor plumping), so many of the herbs mentioned wouldn't even grow in their area and they couldn't obtain them. Would they have been able to obtain a gold candle? No, because it would be too costly or overly complicated to get their hands on a golden candle. So they made do with the herbs, crystals, and white/yellow/natural colored candles they had at hand, not worrying about the supposed rules involving colors and such. The success of your magick depends on your INTENTION, not on which color candle you used, whether or not you did your Casting naked or in a robe, or if you had any special herbs at your immediate disposal or if you're in a coven or not. Books like this, which insist on all these things, really tick me off. If you're a beginner, DO NOT LISTEN TO THAT. Magick should never be so strict. That feels too much like Abrahamic religions, not this.