Invasion!, Book 2.
Long ago, before the dawn of civilization, they were banished to the realm of nightmares. Now the terrors are real...
A generation ago, another Starship Enterprise fought off a ship of exiled aliens intent on conquering all of the Alpha Quadrant. Starfleet thought the foe had been repelled forever – until now. The Furies have returned in might warships even more powerful than before. But their weapons are more than merely physical, for these aliens are the origins of all the demons and monsters of ancient myth, and they have found a way to project fear directly into the minds of their enemies. To defeat the Furies, and save the Federation, Picard and the crew of the U.S.S. Enterprise must first conquer the darkest terrors of their unconscious minds.
Dean Wesley Smith is a science fiction author, known primarily for his Star Trek novels, movie novelizations, and other novels of licensed properties such as Smallville, Spider-Man, X-Men, Aliens, Roswell, Men in Black, and Quantum Leap. He is also known for a number of his original novels, such as The Tenth Planet series, on which he collaborated with his wife, author Kristine Kathryn Rusch. They have also collaborated on other novels, including some of their Star Trek books.