Challenger
New Earth, Book 6.
Far from the reaches of the Federation, the Starship Enterprise has been guiding the development of a once obscure planet upon whose fate the future of the galaxy may now depend. The Enterprise has been the sole representative of the Federation, fighting a constant battle to protect the colonists from enemy aliens and standing alone against all those who have their own designs on the colony world.
CHALLENGER
But all adventure come to an end. It is time for Captain Kirk and the Enterprise to turn over the guardianship of the colony to another ship and crew. The new ship arrives in the midst of a deadly attack on the colony – and is destroyed. With the Enterprise off fighting a new and powerful enemy that threatens the colony as well as its enemies, Commander Nick Keller, first officer and ranking survivor of the decimated crew, is marooned and at first alone -- but he must find a way to complete his original mission and come to the aid of the Enterprise in what might be its most desperate hour.
Diane Carey
Diane Carey (born 1954) is an author of historical fiction and science fiction who is perhaps best known for her work in the Star Trek franchise. She is the co-creator, with John J. Ordover, of the spin-off series, Star Trek: New Earth, and its continuation series, Star Trek: Challenger.
Among her other Star Trek novels are the original series books Star Trek: First Frontier, Starfleet Academy, the Starfleet Academy novel Cadet Kirk, the Star Trek: The Next Generation novel Ghost Ship, and the Star Trek: Deep Space Nine novelization of the two-part episode "The Way of the Warrior."
Star Trek: The Original Series (numbered novels)
Star Trek: The Original Series (numbered novels) consists of ninety-seven books. The current recommended reading order for the series is provided below.
Main series Star Trek: The Original Series