This fourth edition of selecta of my work on the stability of matter contains recent work on two topics that continue to fascinate me: Quantum electrodynamics (QED) and the Bose gas. Three papers have been added to Part VII on QED. As I mentioned in the preface to the third edition, there must be a way to formulate a non-perturbative QED, presumably with an ultraviolet cutoff, that correctly describes low energy physics, i.e., ordinary matter and its interaction with the electromagnetic field. The new paper VII.5, which quantizes the results in V.9, shows that the elementary no-pair version of relativistic QED (using the Dirac operator) is unstable when many-body effects are taken into account. Stability can be restored, however, if the Dirac operator with the field, instead of the bare Dirac operator, is used to define an electron. Thus, the notion of a bare electron without its self-field is physically questionable."

Suppose someone claimed that we are not running out of petroleum? Or that life on Earth began below the surface of our planet? Or that oil and gas are not "fossil fuels"? Or that if we find extraterrestrial life it is likely to be within, not on, other planets? You might expect to hear statements like these from an author of science fiction. But what if they came from a renowned physicist, an indisputably brilliant scientist who has been called "one of the world's most original minds"? In the The Deep Hot Biosphere, Thomas Gold sets forth truly controversial and astonishing theories about where oil and gas come from, and how they acquire their organic "signatures." The conclusions he reaches in this book might be at first difficult to believe, but they are supported by a growing body of evidence, and by the indisputabel stature and seriousness Gold brings to any scientific enterprise. In this book we see a brilliant and boldly orginal thinker, increasingly a rarity in modern science, as he developes a revolutionary new view about the fundamental workings of our planet. Thomas Gold is a member of the National Academy of Sciences, a Fellow of the Royal Society, and an Emertius Professor at Cornell University. Regarded as one of the most creative and wide-ranging scientists of his generation, he has taughtat Cambridge University and Harvard, and for 20 years was the Director of the Cornell Center for Radiophysics and Space Research.