Operation Shield

"The adventures of Cassandra "Sandy" Kresnov, the ultimate synthetic soldier who was made by the League, but defected to her former enemy, the Federation. Explosive action sequences and a focus on character make the Cassandra Kresnov novels unique in SF"--

Cassandra Kresnov is a highly advanced hunter-killer android. When she discovers that the technology that created her has been misused in her former home and now threatens all humanity with catastrophe, she returns home to Callay, and finds that other Federation member worlds, exhausted by the previous thirty-year-war against the League, are unwilling to risk the confrontation that a solution may require.