Here is the list of 125 Science Questions (in PDF format).
Is your field well-represented on the list? If not, what do you think are the most important questions in your field?
Several short essays accompanied the list of questions:
Editorial - Donald Kennedy, editor in chief
What Don't We Know? - Donald Kennedy and Colin Norman
In Praise of Hard Questions - Tom Siegfried
All of this material is also available at Science Magazine, in many short PDF's.