Cannonballs and Honeycombs
Thomas C. Hales
The author has proved the Kepler Conjecture--that the standard way of stacking oranges or cannonballs is at least as efficient as any other way--and a conjecture about honeycombs. This is his first published discussion of the proofs, and he offers insights into the geometry and analysis that he uses.

Communications Security for the Twenty-first Century: The Advanced Encryption Standard
Susan Landau
The National Institute of Standards and Technology is conducting a competition for a public cryptosystem suitable for the beginning of the twenty-first century, with the winning candidate to be announced later in 2000. Landau describes the mathematics and politics behind this competition.

Teaching Geometry According to Euclid
Robin Hartshorne
A noted algebraic geometer writes about teaching geometry to undergraduates with Euclid's and Hilbert's geometry at the base and with modern algebra added later. There is no need for real numbers, and the true essence of geometry can develop naturally and economically.