The book The RNA world, which is reviewed on page 997 of this issue of Nature Structural Biology, covers research that seeks to understand the origin of life on Earth and notes that the idea of a 'prebiotic soup' has become part of the mythology of evolutionary research. This Darwinian idea that life arose in a pond containing all of the necessary building blocks is indeed a pleasing concept. However, it seems that there is now little hard evidence, based on current estimations of the primordial atmosphere, to support the idea that a large variety of prebiotic compounds formed at high local concentrations. Thus, the term 'prebiotic soup' is probably not terribly accurate, as it suggests a rich stock of diverse material.

Here we highlight some of the work of two researchers whose elegant experiments attempted to recreate early atmospheric conditions. Although the geophysical relevance of the conditions used is questionable, the success of these experiments in producing new compounds from the most basic of ingredients has clearly promoted the idea of a 'prebiotic soup'. Walther Löb (in 1906 and 1914) showed that a few types of aldehydes and the amino acid glycine could be produced in a cold plasma discharge system containing a mixture of compounds such as carbon dioxide, ammonia, and water. S.L. Miller (beginning in 1953) extended this line of experimentation, showing that numerous types of amino acids and other organic compounds could be produced under similar sets of reducing conditions.