The 'outward urge' was a factor in the Troon inheritance. Successive generations of Troons, looking up at the stars, heard the siren voices that called them out into Space. And, as the frontiers of Space receded, there was usually one Troon, if not more, out there, helping to push them back. The four exciting episodes related here deal with the parts they played in the building of the Space Station, the occupation of the Moon, the first landing on Mars and the trouble about Venus. John Wyndham, author of The Day of the Triffids and The Kraken Wakes, stays strictly on the tram-lines of future possibility in this audiobook, which he has written in collaboration with Lucas Parkes as technical adviser. In an age in which what goes up need not necessarily come down, the likely adventures of the Conquistadors of Space are every bit as exciting as any world menaced by triffids.