by Jane Yolen (1998)
Commander Toad leads the lean green space machine "Star Warts" to find new worlds but runs into trouble when he sets course for home.
Julia Riding
Eking out a desperate existence as a renegade with the other Portkids who hide in the old tunnels under a spaceport on Mars, the teenager known as Streak stumbles on clues to the sabotage plaguing the entire solar system.
Robert Westall
In a small village, Ralph, a young shepherd, discovers a weird pile of stones. By digging into the stones, he discovers a strange "sleeping" creature with ointments and a dangerous weapon buried alongside. Before he knows it, he has awakened a dangerous and terrifying secret.
David Ward
When Ryan Graham goes to New Denver to interview an arrogant scientist who plans a daring experiment in time travel, the Graham family and others are drawn into a race to keep the universe from being destroyed.
(by) Sylvia Engdahl
A young woman is sent into danger on a planet poised on the brink of nuclear war, forbidden to interfere with its people's natural course of evolution or to reveal her alien origin. Her fellow-agent is not properly trained to work in the field and his compassion may lead him to intervene, thereby unintentionally bringing about the very disaster that he is trying desperately to prevent. She faces an agonizing choice: side with a renegade agent, ot stop him at any cost. Although this novel has the same heroine as *Enchantress from the Stars* it is not a sequel but a completely independent story not intended for readers below high school age. The 2003 edition contains significant updating and should be read in preference to earlier editions.