'Sixteen-year-old Julian is just the sort of boy other boys (and girls too) like to read about. Known to his friends as "The Master Mind", Julian is of a highly inventive nature and his father being a wealthy Australian ranch-owner he has both money and space for his experiments. A rocket-car, a harpoon gun, an aero-car, are only a few of Julian's bright ideas and if they don't always work out quite the way they are meant to - well, that only adds to the hilarity and excitement.
'But the Master Mind's ingenuity is not limited to scientific problems only; it is responsible for all sorts of devices for helping his friends Snoddy and Percival and for the final outwitting of their enemies, those four unlovely youths known as the Tiger Gang. Victory goes first to one side and then the other until the Gang finally retire vanquished. We shouldn't be surprised, however, if they turn up again, scowling as blackly as ever, in another book.' (Dust jacket)