This volume is fourth in the much-acclaimed 'AMS' series, ""What's Happening in the Mathematical Sciences"". The lively style and in-depth coverage of some of the most important 'happenings' in mathematics today make this publication a delightful and intriguing read accessible to a wide audience. High school students, professors, researchers, engineers, statisticians, computer scientists - anyone with an interest in mathematics - will find captivating material in this book. As we enter the 21st century, ""What's Happening"" presents the state of modern mathematics and its worldwide significance in a timely and enduring fashion.Featured articles include: 'From Wired to Weird', on advances that are encouraging research in quantum computation; 'A Prime Case of Chaos', on new connections between number theory and theoretical physics; 'Beetlemania: Chaos in Ecology', on new evidence for chaotic dynamics in an actual population; 'A Blue-Letter Day for Computer Chess', on the mathematics underlying Deep Blue's victory over Garry Kasparov; and, much more!