Two of the things for which we can be most grateful to Great Britain are Sir Isaac Newton and the Royal Society of London for the Improvement of Natural Knowledge, otherwise known simply as the Royal Society. Newton, perhaps the greatest scientist who ever lived, lies entombed in Westminster Abbey, but the Royal Society, of which Newton was President for 24 years, lives on as the oldest and most prestigious learned society still in existence ever since its founding in 1660. The Royal Society is the independent scientific academy of the United Kingdom, dedicated to promoting excellence in science. The motto of the Royal Society, found on its official seal, is Nullius in Verba which is Latin for On the words of no one, which proclaims the Society’s commitment to scientific truth established on the basis of experiment rather than on the basis of mere cited authority.

This issue of the Philosophical Transactions contains 19 papers presented by a number of leading astrobiologists and origin-of-life scientists at a Discussion Meeting held at the Royal Society on Feb. 13–14, 2006. It is a beautiful cornucopia of stimulating science at the frontiers of our knowledge of how life originated on the planet Earth billions of years ago.

In the introduction to the volume, the able editors Sydney Leach FRS, Ian Smith FRS, and Charles Cockell give concise capsule summaries of each of the contributions to the book in the order in which they appear.

The highlights of these papers, from my point of view, are as follows:

P. Thaddeus gives a stunning list of over 130 known interstellar molecules, many of them organic chemicals which could have fueled the rise of chemical and eventually biological evolution on the primitive Earth. One of the most fascinating molecules found in space is corannulene (C20H10), a unique PAH (Poly Aromatic Hydrocarbon), which is one-third of a C60 buckyball.

Max Bernstein gives a very nice summary of terrestrial and also extraterrestrial sources of organic molecules including particularly IDPs (Interstellar Dust Particles) that could have supplied stock chemical for the processes that led to the origin of life on the early Earth. This paper includes some pretty graphics and photographs.

Monica Grady and Ian Wright give an interesting survey of carbon cycling on the early Earth and on Mars and interpret what this tells us about our own Earthly biosphere and the possibility of finding a Martian biosphere. We need to find out many more things about Mars, but as of the present time, it looks as though Mars does not possess a biosphere.

M. Anand, S. Russell, R. Blackhurst, and M. Grady give an extensive study of iron isotope data found in terrestrial rock samples and in Martian meteorites in an attempt to see if such data can aid us in looking for biosignatures on Mars and beyond. Again, we need considerably more data from Mars, but at least so far, no biosignatures based on iron isotope analysis have been found on Mars.

Jonathan Lunine, a fount of planetological wisdom, gives an excellent overview of the physical formation of the Earth from colliding planetesimals, asteroids, and smaller fragments, and what the resulting physical conditions were like on the primitive Earth. Included are fascinating color graphics of computer simulations showing how small fragments of rock and metal get compacted into larger fragments and eventually end up as rocky planets such as the Earth. Lunine then goes on to discuss some interesting possible environmental analogues to the early Earth, namely Venus, Ceres, Io, Europa, and Titan.

James Kasting and M. Tasewell Howard give a detailed explanation for why they believe that cold temperature theories of the origin of life should not be ruled out of consideration by those scientists investigating the conditions for the emergence of life on the early Earth. I will admit, as a reviewer, at this point, that I personally am a supporter of hot temperature theories of the origin of life.

Alan Schwartz, a grandmaster of phosphorous chemistry, gives a superbly lucid exposition of the importance of this element in the origin of life, along with a wealth of details about the different chemical forms in which phosphorous could have first made its entrance into biological chemistry. I especially like the fact that Schwartz shows how heat easily converts monophosphates by thermal dehydration condensation into polyphosphates which are believed to have been the first chemical reservoirs for supplying metabolic activation energy for the origin of life.

William Taylor gives a detailed model of a possible early Earth RNA-directed RNA polymerase (a ribopolymerase) which is required by the RNA World hypothesis as a precursor to the ribosome. This paper has some very nice three dimensional molecular computer generated graphics. Taylor shows that his model works best at a temperature of 90°C, which fits in with a hot theory of the origin of life.

Eörs Szathmáry presents interesting mathematical models of replicators and reproducers in the origin of life and compares them to the mathematical models of other investigators, such as the hypercycle models of Eigen and the graded autocatalysis replication domain (GARD) model of Segré and Lancet.

James Ferris, a premier fabricator of model prebiotic genes, presents a guided tour of the fascinating chemistry involved in such constructions and his use of the clay montmorillonite in catalyzing the polymerization of nucleotides into nucleic acid oligomers of up to 50 units long.

Günter Wächtershäuser, a chemist/patent attorney (like myself), gives an intriguing account of a postulated pioneer organism in his volcanic iron–sulphur world. The interesting thing about this proposed pioneer organism is that it is, in a sense, an unbounded metabolic network which begins on the two-dimensional surfaces of minerals such as pyrite. Wächtershäuser then goes on to postulate how vesicle-bounded protocells would have evolved from this pioneer organism. This theory, based on volcanism, is also a hot theory of the origin of life.

David Deamer, a lipidologist of great repute, Sara Singaram, Sudha Rajamami, Vladimr Kompanichenko, and Stephen Guggenheim set out to test some of the properties of Charles Darwin’s famous “Little Pond” by using pools of hot springs as analogues for such pond by throwing into such pools the organic solutes of amino acids, nucleobases, a fatty acid, and glycerol. The fate of such molecules in such heated milieus is duly reported.

Don Canfield, Minik Rosing, and Christian Bjerrum present an authoritative analysis of various anaerobic metabolisms based on various hydrothermally based ecosystems that preceded the generation of an aerobic atmosphere on the early Earth. Hyrogen-based ecosystems, a sulphur-based ecosystem, an iron-based ecosystem, and a nitrogen-based ecosystem are discussed.

Karl Stetter, a hyperthermophilephile (a lover of hyperthermophiles), gives extremely persuasive evidence that the Last Common Ancester (LCA) of all life on Earth was a hyperthermophile. Presented is a small subunit RNA-based phylogenetic tree showing that the root of the Tree of Life is composed entirely by hyperthermophiles. Stetter presents beautiful microscopic photographs of four different such hyperthermophiles and various environments in which such hyperthermophiles are found.

Charles Cockell provides an interesting analysis of how, during the Hadean Period of the early Earth, impact craters from comets, asteroids, and meteors may have provided locales for “warm little ponds” of the Darwinian sort along with warm bigger lakes where life could have gotten started. This fits into essentially a hot theory of the origin of life.

Frances Westall, a top-flight micropaleontologist, Cornel de Ronde, Gordon Southam, Nathalie Grassineau, Maggy Colas, Charles Cockell, and Helmut Lammer present an impressive array of multidisciplinary evidence that well developed microbes inhabited the Earth up to 3.5 billion years ago, when the flux of UV radiation reaching the surface of the Earth was presumably much higher than at the present time. They also confirm, at the same time the fact that had recently been disputed in some scientific quarters that the antiquity of life does indeed extend backwards in time at least 3.5 billion years if not further. This paper includes an impressive array of photographs.

In the last paper presented, Joshua Jortner, ably summarizes and reflects upon a number of points made in the previous papers given in this Royal Society volume. What seems reasonably clear is that the emergence of life on the early Earth took place in the following general manner: Simple prebiotic molecules such as H2, H2O, CH4, NH3, CO2, HCN, H2S, etc., reacted with the input of energy to form monomers such as amino acids, nucleobases, sugars, phosphates, etc., which then underwent self-organized polymerization to form the first biomolecules that included polypeptides, proteins, nucleic acids, and oligomers, which such protobiomolecules than underwent further self assembly to form the first cells on the early Earth. As is usually the case in such complicated matters, the ‘devil’ is in the details of the whole process. What these details are still remains to be answered before we will be able to say that the origin-of-life problem on the early Earth has been definitely solved.

In some ways, the origin-of-life problem is like a black hole. So singularly fascinating is this problem that all scientists of a truly inquisitive mind will immediately feel its attraction. For those scientists who follow an inclination to investigate this problem much more closely and in much greater detail, there often comes a point where they pass beyond an event horizon of intense interest from which there can be no escape. They may not know where they are going to end up, but they do know that there is no turning back. Such are the leading scientists in the field who present their best thoughts on the origin-of-life problem in this truly excellent volume of the Royal Society, and we the readers are much better off for it. Some of us may even follow them in.