Note: Expansion of 2 previously published stories - "Novice" (1962) and "Undercurrents" (1964).

Synopsis: From the back cover of the Ace first edition: "If you use your psi power, it will mean trouble. If you read the wrong minds, it will mean trouble. But if you find out about us - we will rally the universe against you! The story of Telzy Aberdon, the one in a million mentalist whose startling mutant abilities might mean miracles for galactic society if she ever learned to use them fully, is a brilliant novel of the interstellar future. For when first she tuned in on the secrets of an alien race, it was just a minor alarm. But when finally her uncharted talents stood squarely in the way of a planet-seizing plot, it was a full-fledged red alert for a galaxy's undercover contestants."