Issue No. 03 - May/June (2001 vol. 3)
In 1900, David Hilbert presented 23 problems at the International Congress of Mathematicians held in Paris. Hilbert's problems spanned the spectrum from rather trivial (Problem 3 on the equality of the volumes of two tetrahedra) to the probably impossible (Problem 6 on the axiomatization of physics). Nonetheless, they challenged many of the leading scientists and mathematicians of the 20th century and set the tone for mathematical research, especially in the early part of the century.
Francis Sullivan, George Cybenko, "Guest Editors' Introduction: Tomorrow's Hardest Problems", Computing in Science & Engineering, vol. 3, no. , pp. 40-41, May/June 2001, doi:10.1109/MCSE.2001.10007