In book 1, The Field Guide, Jared, Simon, and Mallory Grace move into their great-great uncle Arthur Spiderwick's house. After some strange, unexplainable, destructive events, Jared finds a field guide that Arthur wrote eighty years ago-- about faeries. They then discover the cause of their troubles, a brownie/boggart named Thimbletack. In book 2, The Seeing Stone, Simon gets kidnapped by goblins and Jared must rescue him, with Mallory's help. But first, he must be able to see the monsters. In book 3, Lucinda's Secret, the Grace siblings talk with their supposedly crazy Aunt Lucinda about the Field Guide, and they begin to uncover some of the secrets of the book and its creator. In book 4, The Ironwood Tree, Mallory is kidnapped by dwarves and forced into a dress (oh, and a glass coffin, as well), the twins become triplets, and they must wake Sleeping Beauty whilst escaping from a pack of mechanical hounds. Finally, in book 5, The Wrath of Mulgarath, The Grace siblings journey to an ogre's dragon-guarded fortress made of trash in a final, desparate attempt to stop a plot to overthrow the world.
Whew, that's a lot of stuff.
These books are not just wonderfully packaged. If the imagery the authors give you isn't enough, there are many great sketches that let you see how easy it was to make this into a movie. If you're anything like me, you'll race through each page-- but don't forget to read the rhymes at the end.
Their world is closer than you think.