The Nature Collections series bring together important papers around a particular area of scientific research. Published both in print and online, they make perfect reference tools.

The latest collection, just published and freely available, is Metagenomics, in which Nature presents a selection of papers that combine the latest techniques to explore whole microbial communities and track individual species in uncultured samples ranging from sea water to soil. You can read the collection online here, and request a free printed copy here.

From the Editorial introducing the Metagenomics collection, by Senior Nature Editor Chris Gunter:

A picture of a microbial community as a whole can be pieced together from the number and diversity of, for example, 16S ribosomal RNA genes. Moreover, individual species can be tracked by the presence or absence of genes such as rhodopsins in aquatic samples, or metabolic enzymes in the soil or the host intestine.

The articles in this collection use combinations of the latest sequencing technologies to describe many environments for the first time and to reinterpret those that we see every day.

For instance, the fascinating marine worm Olavius algarvensis lacks a mouth and a gut, but manages to survive thanks to an amazing symbiotic relationship with bacteria. Metagenomic analysis allowed the first description of this symbiosis.