Mars, in Earth's Image
Scientists have a wildly ambitious plan to transform the fourth planet from the sun into an exact duplicate of the third.
Divided Selves
To get to the bottom of schizophrenia, two scientific rivals are seeking help from some unusual twins--twins who are identical in all respects but one.
The Dating Game
By tracking changes in ancient atoms, archeologists are establishing the astonishing antiquity of modern humanity.
Alzheimer's Stepchild
A neuropathologist defies conventional wisdom when he swears there's a connection between aluminum and Alzheimer's.