Editorial
Varietal Responses of Crops to Atmospheric CO2 Enrichment: Why is it important to document such responses? ... and to do so under standard field conditions?

Medieval Warm Period Record of the Week
This issue's Medieval Warm Period Record of the Week comes from the Naja Lake, Lacandon Forest, Chiapas, Mexico.

Subject Index Summary
West Antarctic Ice Sheet (Mass Balance): Where has it been, in terms of positive or negative? ... and where is it heading?

Journal Reviews
The Atlantic Meridional Overturning Circulation: How has it varied over the 20th century?

Rainfall Extremes at Uccle, Belgium: 1898-2004: What do they reveal?

The "Closed" System of Symbiotic Algae Acquisition by Corals: Are there any circumstances under which the system may be "opened"?

Central Indian Ocean Coral Recovery from 1998 Bleaching: Has there been little or much reestablishment of the most devastated species?

CO2 Enrichment of a CAM Bromeliad: Was its response positive or negative? ... and how good or bad was it?