(from Scholastic Book Services 1972)
Are the Old Martians really a lost race — just withered mummies lying in dark caves? Or are they still alive — somewhere on the red planet?
Sally and Jim must find out. They must help their father discover if the Old Martians still exist. His life work as a scientist is at stake!
But it's not easy. They are only visitors to the Mars colony in the year 2017. And no one really wants them there.
[None on record]