Book 2 of 4 in a mini-series entitled The Dominion War. A novelization of the Season 5 Episode 26 in the television series Star Trek: Deep Space Nine.
"Faced with the realization that the Dominion are taking over the Alpha Quadrant, Sisko decides to mine the entrance to the wormhole with self-replicating cloaked mines, thus beginning the Dominion War."
Note: Elim Garak plays a moderate role.