As you are probably aware, "The Source of Magic" is the second book in the Xanth series. A co-worker turned me on to the series by lending me the sixth book ("Night Mare"), which led me pick up the first 16 books through an ebay auction.
I have heard that, after a while, the Xanth books get repetitive or dull, but "The Source of Magic" is near the beginning of the series, and everything is fresh and tight. What do I mean by tight? Well, the laws of magic in Xanth are well-formed and internally consistent. Lots of fantasy movies, in particular, do not adhere to internally consistent rules, and as a result, they get annoying. A prime example is Michael Crichton's "Timeline," where he babbles on about quantum theory in an effort to demonstrate that his book is not about time travel; yet, a major plot point could only work if in fact a person traveled back in time. That's annoying.
"The Source of Magic" (and "A Spell for Chameleon," the first Xanth book) are not like that. They follow the rules, and once you understand the secret about Bink (the main character), you marvel at how well everything fits together.
Anyway, this is a classic "quest" type of story: a group of adventurers -- Bink, a human with a special magical talent; Crombie, a human soldier transformed into a griffin (part-eagle, part-lion); Humfrey, a human Magician; Grundy, a golem; and Chester, a centaur -- go on a mission to find the source of magic in the land of Xanth. Along the way, they meet a dragon, an ogre, a village of women, a siren and a gorgon (kind of like Medusa), and all sorts of other creatures. Once they find the source of magic, Bink has to make an awfully difficult ethical and moral choice.
Later Xanth books get more and more pun-filled; you see some of them here, such as the desert known as "eye scream," made from the eyes of scream birds -- not to be confused with "eye smilk." But apart from the puns, this book is often quite funny, especially since the griffin and the centaur are constantly squabbling against each other.
