Heinemann, London, 1970, 7th pr.  ISBN 0-434-34919-4.  Hard cover, 251 pages.  Blue boards with gold lettering on spine; corners sharp with just a touch of wear at lower spine end; faded water mark on top page block, age spotting on outer page block; binding sound.  Price-clipped dust jacket has edge and cover wear, old water marks, scar at upper left corner.  Red marks on front paste-down and end paper, probably from water/moisture to jacket.  Interior clean and unmarked with lightly tanned pages; some black & white illustrations.  ‘A cloud of gas … approaches the solar system on a course that in little more than a year is reckoned to bring it between the Sun and the Earth, causing incalculable changes on our planet.  Together with top-ranking experts in other fields and from other countries, Chris Kingsley, Professor in Astronomy at Cambridge, is sent to a highly secret establishment set up to advise the British Government.  During the months that follow the nature of the cloud becomes more and more awe-inspiring, while the advisers, under Kingsley’s influence, becomes less and less content to remain purely advisory.  Politicians and scientists, and their peculiarities, provide a human, often a humorous element, in this gripping and alarming story.  “How much of this steps outside the bounds of possibility?” the author asks in his preface, and answers:  “I believe very little.”’ (from front flap)