The resource dispersion hypothesis (RDH) asserts that, if resources are heterogeneous in space or time, group living might be less costly than was previously thought, regardless of whether individuals gain direct benefits from group membership. The RDH was first proposed more than 20 years ago and has since accumulated considerable support. However, it is sometimes discredited because a priori tests of specific predictions are few, relevant variables have proved difficult to define and measure, and because its assumptions and predictions remain unclear. This is unfortunate because the RDH provides a potentially powerful model of grouping behavior in a diversity of conditions. Moreover, it can be generalized to predict other phenomena, including spacing behavior in nonsocial animals and utilization of resources other than food. Here, we review the empirical support, clarify the predictions of the RDH and argue that they can be used to provide better tests.

Russia's first decade after the collapse of the Soviet Union has been simultaneously tumultuous and transformative. For most of the 1990s the Russian economy was in free fall, the legal system in absentia, and the majority of citizens engaged primarily in survival efforts. Not surprisingly, the former superpower also struggled to adapt to its greatly diminished means and status.

Russia after the Fall examines Russian politics, economics, society, and foreign and security policy. Internationally renowned experts provide retrospective analyses of how Russia has fared in its reform efforts and a prospective look at the challenges ahead. This book will be of interest to scholars, students, and a general audience seeking to better understand where Russia has been and where it is going.

Why do some peace agreements successfully end civil wars, while others fail? What strategies are most effective in ensuring that warring parties comply with their treaty commitments? Of the various tasks involved in implementing peace agreements, which are the most important? These and related questions--life and death issues for millions of people today--are the subject of Ending Civil Wars.

Based on a study of every intrastate war settlement between 1980 and 1998 in which international actors played a key role, Ending Civil Wars is the most comprehensive, systematic study to date of the implementation of peace agreements--of what happens after the treaties are signed. Covering both broad strategies and specific tasks and presenting a wealth of rich case material, the authors find that failure most often is related not only to the inherent difficulty of a particular case, but also to the major powers' perception that they have no vital security interest in ending a civil war.

The celebration in Prague should have been more raucous. The most successful alliance in world history has extended to corners of Europe unimaginable just a few years ago. The military capacity gained for the North Atlantic Treaty Organization from expansion is minimal but the political returns will be fantastic. More than any other institution, NATO has helped make Europe democratic, peaceful and whole. What is particularly striking about the new members -- Slovenia, Lithuania, Estonia, Latvia, Bulgaria, Romania and Slovakia -- is how many of them emerged from Communist rule with no democratic traditions. The pull of NATO, the desire to join this Western club, created real incentives for democratic consolidation.

Western democracies face increasing constraints on the use of their overwhelming military power. The classical logic, legitimacy and effectiveness of employing force to safeguard national interests apply less and less. State and non-state adversaries threaten important and even vital Western values and interests but are seemingly underterred by - or even inspired by - Western military superiority. At the same time, phenomena such as globalisation, the growing transparency of the battlefield and changing Western value systems subject civilian and military leaders to mounting pressure to wield military power selectively and to use increasing discrimination in choosing means as well as ends.

STANFORD, Calif.— More than 100 hostages are dead after Russian authorities used an unidentified gas to incapacitate terrorists holding 750 people in a Moscow theater. Nearly all of the deaths were due to the gas, which Russian authorities have so far refused to identify.

Press coverage has rightly emphasized grief and the question of why antidotes were not immediately available. It has then focused on whether the Russians' use of gas was a violation of the 1997 Chemical Weapons Convention. But this focus, while important, risks overlooking the big picture when it comes to Russian chemical weapons.

The Chemical Weapons Convention is a global treaty with more than 170 signatory nations. It bans the production, acquisition, stockpiling, transfer and use of chemical weapons -- the first arms-control treaty to outlaw an entire class of so-called weapons of mass destruction. It also requires its signatories to declare and destroy, by certain deadlines, the chemical weapons they possess.

Since the 1925 Geneva Protocol prohibiting the use of chemical and biological weapons in war -- a reaction to gas attacks in World War I -- the world has struggled to ban these weapons. In part, this is because of their indiscriminate nature.

After Sept. 11, 2001, it seems all the more important to eliminate stocks of such weapons because access to them could confer such power to terrorists. In a world with 70,000 metric tons of chemical weapons agents, some of which may be vulnerable to terrorist theft, the verified elimination of these weapons will be a step toward greater security for all. This is true despite the disturbing fact that Iraq, North Korea and certain other nations are not parties to the convention.

The weapons convention permits the production and use of riot-control agents for law enforcement purposes. Until the Russians inform us of the agent used, whether they were in violation of the convention will remain uncertain. But renewed attention to Russian chemical agents should focus on a more important issue. Russia retains some 40,000 tons of chemical warfare blister agents and nerve gas. It is required by the convention to destroy them, and the United States and European nations have agreed to help. But American efforts under the Nunn-Lugar Cooperative Threat Reduction program are stalled in Congress.

The Cooperative Threat Reduction program began in 1992. It provides expertise and funding to help the former Soviet Union secure and destroy nuclear, chemical and biological weapons and materials. Progress with chemical and biological weapons has been especially slow, and the Russians have too often been less than forthcoming.

Of particular concern has been the Russian stockpile at Shchuch'ye, a town near the southern border with Kazakhstan. The Shchuch'ye stockpile contains nearly two million artillery shells -- and hundreds of missile warheads -- filled with nerve gas or other chemical weapons. Although stockpile security has been upgraded with help from American financing, the threat of insider theft remains real. Many of the shells are in working condition, and they are small and easily transportable.

Cooperative Threat Reduction funds have paid to design a plant for construction at Shchuch'ye to destroy these weapons securely and safely. The Pentagon wants $130 million for construction in the new fiscal year. Russia, its economy still weak, won't do this without American assistance. But the program is currently stalled in a Congressional conference committee due to a disagreement over granting the president authority to proceed with the project.

The Bush administration's new national security strategy has emphasized the destruction of weapons of mass destruction by pre-emptive strikes if necessary. But at Shchuch'ye alone, the United States could destroy more than 5,000 tons of ready-to-use weapons of mass destruction through a different kind of pre-emptive strike -- action by a Congressional committee.