He's been out of the military a little more than a year and admits having to "down shift" to life as a civilian.
Gallagher was one of five veterans who also happened to be writers taking part in a reading at The Old Stone House in the Park Slope section of Brooklyn.
Gallagher' book is titled, "Kaboom, Embracing the Suck in a Savage Little War."
"Nobody wants to talk about it, says Gallagher, "but there is an excitement that goes along with being in danger on a daily basis that sometimes makes life after coming home difficult. It took patience from family and friends to help me make the transition."