Hidden worlds. [electronic resource] . — Washington, D.C. : : National Geographic Society,, c1981.. — 104 p. : : ill. (some col.) ; 28 cm. - Books for world explorers.
Includes index. Pocket contains a pamphlet, Far-out fun! (24 p.), a pair of 3-D glasses and a poster.
Bibliography: p. 103.
Think small / by Edith Kay Pendleton -- Beyond earth / by Kathryn Allen Goldner and Carole Garbuny Vogel -- The inside story / by Catherine O'Neill -- Wider horizons / by Eleanor Felder -- More light on the subject / by Kathryn Allen Goldner and Carole Garbuny Vogel -- Catch all the action / by Catherine O'Neill -- Who discovers hidden worlds? / by Glenn O. Blough.