I'll admit: I'm a sucker for Flatlandia.

I wasn't always this way. The person I have to thank for this curious addiction is Rudy Rucker. He introduced me to A. Square and his two dimensional cohorts back when I was questing for the edges of the universe and anything was possible.

He did it with The Fourth Dimension.

Thanks in large part to Rudy Rucker, Douglas Hofstadter and Robert Heinlein I realized there are no edges. Everything is not only possible, but probable. Tonight I spent some hours re-re-reading various sections of this book, getting a bearing on my internal compass, plotting a new path based on where I've been.

Here are some points on the map of reality Rucker provided me:

- Flatland

- the fourth dimension as time and as space

- Necker cubes

- hypercubes, hyperspheres and tesseracts

- hyperspace, Howard Hinton and Hinton cubes

- pre-atomic theory explanations of reality

- matter and space as fluid conceptual frameworks

- wormholes, Einstein-Rosen bridges, warped and folded space

- Einstein's general and special theories of relativity

- ana/kata and fact-space

- liquor thieves from the next dimension

It goes on and on. Rucker introduced to me or expanded to early understanding so much in these pages... the cumulative effect is staggering. Best of all, and I believe the main reason for this volume's success: cover to cover, the book is fun. It's not academic, dry or difficult reading at any point, and the eccentric, engaging style slips past the "learning something new" barrier in disguise. I can imagine Rucker with the White Rabbit sitting next to him laying out writing advice on the manuscript.

Each chapter contains mind-bending puzzles for you to do (probably the Rabbit's idea) and if you're very diligent you'll be able to visualize four dimensional objects by the end of the book.