NASA's twin Mars Exploration Rovers have clocked up more than 1000 days of geological exploration since their launch in January 2004. Nature presents the latest peer-reviewed papers to come from analysis of the rovers' data alongside an archive of news & views, articles, letters and a FREE image gallery.

Is organic the future of farming? In its pure form, maybe not. But elements of the organic philosophy are starting to be deployed in mainstream agriculture. Here, Natureanalyses this trend, assesses the extent of organic farming, and frames the questions on which its wider adoption will depend.

For the past 20 years, David Goldston has been at the heart of forging US science and environmental policy. His Naturecolumn ran from 2007 to 2009 and provided a seasoned insider's take on the interaction between science and politics. From stem cells and energy policy to climate change and space exploration, Goldston has a unique perspective on why things work-or don't work-in Washington DC.

Plant hormones are a family of structurally unrelated small molecules that are central to all aspects of plant growth and development. This is a very exciting time for hormone biologists as the number of hormones identified has doubled in the past decade, and receptors and downstream signalling molecules for the main hormones have been identified. A snapshot of cutting-edge research in the plant hormone field can be obtained in the articles and reviews in this Nature web focus.

Fifty years ago this month Hugh Everett III published his paper proposing a "relative-state formulation of quantum mechanics" - the idea subsequently described as the 'many worlds' or 'multiverse' interpretation. Its impact on science and culture continues. In celebration, a science fiction special edition of Natureon 5 July 2007 explores the symbiosis of science and sf, as exemplified by Everett's hypothesis, its birth, evolution, champions and opponents, in biology, physics, literature and beyond.

Malaria continues to claim a significant number of lives worldwide, estimated at ~ 1 million each year.

The Internet is profoundly changing how scientists work and publish. New business models are being tested by publishers, including open access, in which the author pays and content is free to the user. This ongoing web focus will explore current trends and future possibilities.

Lawyers defending six medical workers who risk execution by firing squad in Libya on charges of deliberately infecting more than 400 children with HIV have called for the scientific community's support. After Naturepublished articles on the issue in late September 2006, the blogosphere amplified the lawyers' initial call for independent scientific review of how the children became infected.

Cancer stem cells are defined as those cells within a tumour that can self-renew and drive tumorigenesis. Rare cancer stem cells have been isolated from a number of human tumours, including haematopoietic, brain, colon and breast cancers. The cancer stem-cell concept has important implications for cancer therapy. However, the generality of the cancer stem-cell hypothesis has also been challenged, most recently in a paper by Sean Morrison and colleagues included in this web focus.

From cell biologists to quantum physicists, researchers are struggling to work out how systems involving large numbers of interacting entities work as a whole. In this collection of Essays, scientists explain how a systems approach, in parallel with the reductionism that dominated twentieth-century science, promises to yield fresh insight, and in some cases, to challenge the most widely held concepts of their field.

An effective vaccine and new drugs to treat HIV/AIDS are urgently needed. These challenges require improved understanding of the biology of the virus, its interaction with infected cells and the immune response. This web focus presents selected recent research papers published in Natureand highlights topical issues in the field.

Natureis proud to present the return of Futures to the mother ship: a forum for the best new science-fiction writing, exploring some of the themes that might challenge us as the future unfolds. Prepare to be amused, stimulated, even outraged, but know this: the future is sooner than you think.