Editorial
The State of the World's Mammals: What are the greatest threats to their continued existence? ... and what is the most important factor in maintaining their current level of global species richness?

Medieval Warm Period Record of the Week
This issue's Medieval Warm Period Record of the Week comes from Kongressvatnet, Svalbard, Western Spitsbergen, Norway.

Subject Index Summary
Medieval Warm Period (Arctic): Is the footprint of the Medieval Warm Period evident in the paleoclimatic records of the northernmost part of the planet?

Journal Reviews
The Paleoclimate of the USA's San Francisco Bay Watershed: How did the climate of medieval times compare with that of modern times?

A Brief (One Millennium) History of the Gulf Stream: Is its strength enhanced or diminished by global warming?

Plant Productivity Responses to Experimental Ecosystem Warming: Have they been mostly positive or negative?

The Water Use Efficiency of Silver Fir Trees in a CO2-Accreting Atmosphere: How did it vary in French forests of the Jura Mountains between 1860 and 1980?

Thrips Feeding on Clover: Are the little plant-juice suckers helped or hindered by rising atmospheric CO2 concentrations?