The fantasy aspects may or may not be real, but I have always interpreted them as being parts of a novel by Julian Fellowes, a dead, fictional author of historical fantasy from the series.
I was trying to figure out what makes these books good. And they most certainly are. At first, I thought it was to make the mundane more than it is, but actually, many of the things happening to the (more or less) contemporary characters are actually quite important and dramatic, yet Crowley keeps an even, slow paced tone that almost deemphasizes them. Things happen like the (kind of) main character’s girlfriend joining a religious cult and a dramatic custody dispute between another character and her ex-husband over their daughter.
For all of them, it’s a spiritual quest for meaning that the world refuses to release to them, or, if it does, slowly and with great difficulty and resistance. But really, I couldn’t even begin to describe what it’s about. A search for meaning by looking to a world that may or may not have really existed (a pre-modern world when magic worked – the land of, not Egpyt, but Ægypt) and a simultaneous account of magical practitioners in a world where magic is vanishing (real life characters like John Dee and Giordano Bruno).