Sir Fred Hoyle and Professor Chandra Wickramasinghe received world wide attention on the publication of their book Lifecloud which argues that life arrived on Earth from outer space. Now, in this equally controversial sequel, they maintain that viruses and bacteria responsible for plagues, diseases, influenzas and the common cold originate in space and are stored deep-frozen in comets which swarm around the solar system and subsequently fall to Earth. By examining the infall of pathogenic material from space and analysing plagues and epidemics, the authors provide startling evidence of the relationship between astronomy and disease.