Pierre Bordage writes science fiction, specialising in space opera and historical fantasy.
Jean-Paul Demoule, an archaeologist at Paris-1 University, is the founder and former president of the Institut d’Archéologie Préventive (INRAP). He is the author of numerous works, including On a retrouvé l’histoire de France (2102).
Roland Lehoucq, an astrophysicist working at the French Alternative Energies and Atomic Energy Commission (CEA), specialises in writing scientific works inspired by fiction: D’où viennent les pouvoirs de Superman? (Where Do Superman’s Powers Come From?), Faire de la science avec Star Wars (Doing Science With Star Wars).
Jean-Sébastien Steyer, a palaeontologist at the Paris Museum of Natural History, writes a column, with R. Lehoucq, for the magazine Pour la Science. He is the author of La Terre avant les dinosaures (2009).

Adapting the form of an ‘Exquisite Corpse’ (a Surrealist technique in which collaborators draw in turn on a sheet of paper, fold it so that only a fragment remains visible, then pass it on to the next collaborator who improvises a new drawing), the four authors of this book have each described a possible planet and imagined the life forms that could have developed there, according to the laws of evolution. We know our planet could be different: but what could it be like?
This ‘exquisite’ planet, created according to the rules of plausibility by an astrophysicist, a palaeontologist and an archaeologist, does not resemble the planet Earth — except for the amazing inventiveness of its creatures. Yet it could have been our planet if chance had taken another direction. The authors’ ‘exquisite’ planet becomes especially fascinating when a science fiction writer adds his final contribution, giving an epic dimension to the scientific and factual descriptions and abolishing the comfortable frontier between science and fiction.
Initially conceived as a scientific essay aiming to define the realm of possibility, the book ultimately took the form of an unusual literary essay, which gradually guides the reader from a purely factual scientific text to a moving science fiction story.