THE PLANIVERSE: COMPUTER CONTACT WITH A TWO-DIMENSIONAL WORLD A. K. Dewdney. Toronto, McClelland and Stewart, c1984. 267pp, paper, $12.95. ISBN 0-7710-2742-7. Grades 11 and up. Reviewed by Jean Farquharson. Volume 12 Number 6 1984 November Since Edwin Abbott's classic, Flatland, was published in 1884, mathematicians have speculated and researched what life would be like in a two-dimensional universe. One of these mathematicians is Dr. A. K. Dewdney, who has created an exciting imaginative world on the planet of Arde, somewhere inside the Planiverse, as an exercise for his computer science students at the University of Western Ontario. From this exercise, he has generated the book in which Yendred, a two-dimensional being, communicates with our world through a computer, believing that he has contacted a spirit-world that he finds as difficult to understand as we do to grasp his world. In order to help us comprehend the concepts introduced to us in a journey with Yendred across Arde, many illustrations and diagrams are included to explain the planet's own sciences, philosophy, technology, and civilization. An appendix contains the "speculations" of Earth scientists about Ardean science and technology, including two-dimensional computing, a 2-D volcano and Planiversal gravity, all of which are a delight to ponder. Dr. Dewdney includes in his acknowledgements major works that influenced him, his university connections, and his contacts through "Computer Recreations," which he writes for Scientific American magazine. This innovative, creative book will stimulate many bright science/mathematics/computer students. Perhaps, leading from this, a group of young hackers will create their own computer adventure based on the wanderings of Yendred on the Planet of Arde in the Planiverse or create another world of four or five dimensions. Jean Farquharson, Brantford C. I. & V. S., Brantford, ON.