Though the Union Navy held a numerical advantage over its Confederate counterpart, the South's forces had one weapon that was not readily available to the North--underwater mines, known at the time as torpedoes. More Union ships were destroyed by torpedoes than by all other means combined. The South's superiority in underwater weaponry can be directly traced to the work of an oceanographer named Matthew Fontaine Murray. Recognizing the South's limited capabilities, Murray persuaded its leaders to develop underwater weapons. This is the first detailed history ever of the South's development and deployment of both offensive and defensive underwater weaponry. Included are many photographs of actual salvaged Confederate mines.