From the preface: Edwin A. Abbott was an English schoolmaster who is best known for his authorship of the 1884 novella Flatland . Abbott had a great idea for a book that teaches some aspects of geometry, inspires the mathematical imagination, and doesn’t bore the reader like a traditional textbook does. Flatland follows the story of a square living in Flatland, a two-dimensional world. The square is visited by a sphere. The sphere tells the square about Spaceland, a three-dimensional world. The square doesn’t understand the third dimension until the sphere takes him there, and the square learns what Spaceland is like. When my dad was a kid, he read Flatland . About forty-five years later, he recommended it as a part of my homeschool math curriculum. We read the book together, and the geometric story blew me away. However, I found the book in some parts to be difficult and frustrating to read: its archaic language, its verbosity, its harsh attacks on English social and political systems that no longer exist, all got in the way for me of the very interesting geometric story. After we had finished our reading, my dad and I agreed that, for all its mathematical interest, Abbott’s Flatland might be nearing the end of its useful life. I told him that I doubted I would recommend it to my own future children as he had done to me. After thinking about this for a while, I suggested to my dad that I make an edited version of Flatland that I could recommend to those future children, and which I could publish through CreateSpace. My dad agreed, so I got to work editing the book with his help. My original conception was to make a “Flatland for Kids,” but as the project progressed, I realized that it is more a “Flatland for Modern Readers” of all ages. This book retells the core of Abbott’s original story. I have stripped away Abbott’s nineteenth-century commentary on the English class system, politics and government, revolutions, religion, and the place of women in society. What remains is the mathematical romance, which is to me, and I think to many others, what makes Abbott’s tale interesting. In addition, Abbott’s ornate and wordy language—he anticipated King Friday XIII’s dictum, “Never use short words when long ones will do”—has been gently updated to a more modern style, which hopefully aids both reading comprehension and pleasure. Also, I have fixed a few errors in Abbott’s mathematical explanations and added a few new elements to augment the story. Lastly, the ending of the square’s story, which to me seemed unnecessarily tragic in Abbott’s telling, has been made much happier.