 It was published in the UK by Faber in 1969 and in the US by Washburn Books under the title Neptune One is Missing.As one of the best of the series, it is very collectable and changes hands at sums of £100-£200 on trading sites.The book begins by announcing the death of Chris Godfrey and his three fellow astronauts after a fire and apparent break-up of their spacecraft as it approaches the orbit of Neptune as observed from Earth.