The first two books really revolve around Gary Seven and Roberta. He does an impressive job of weaving a lot of latter 20th Century history (both Trek and real world) in such a way to give Khan his send off on the Botany Bay.

Here's a Amazon.com review that sums up things nicely:

"Cox's challenge as a 21st Century writer was to mesh this fictional history with such real-life events as India's first nuclear test in 1974, the Bhopal accident and Indira Gandhi's assasination in 1984, the Reagan-Gorbachev Iceland Summit in 1986, and the fall of the Berlin Wall in 1989, among others. In these 20th Century episodes, Gary Seven and Roberta Lincoln (who first appeared in the proposed pilot for Gene Roddenberry's "Assignment: Earth" series)investigate a secret project code-named "Chrysalis." Led by the brilliant but cold-blooded Dr. Sarina Kaur, a team of genetic experts is tweaking human DNA to bring forth a "superior" breed of humanity...a breed which is destined to supplant the existing "flawed" population of the planet.

Cox adds to the fun by adding cameos by other Star Trek characters, including Gillian Taylor from Star Trek IV, Redjac from the Classic Series' "Wolf in the Fold," and Ralph Offenhouse from The Next Generation's "The Neutral Zone." And while his basic plotline resembles a mix of Star Trek and Tom Clancy novels, he also injects some witty puns and inside jokes which lighten the tone of this chilling narrative set in one of Star Trek's "dark times" of humanity's past. "