U.S. Army: 30 Handy Flamethrower Recipes is found on the second floor in the "kitchen area". Coming from DCTA tunnel 014-B Potomac, it's past the caves, when you enter the tunnels again full of raiders. The first stairs on the right, on a shelf. From the Arlington Cemetery entrance, after you pass the "White Line" sign take your first left (a four way junction), then a right (a T intersection). The kitchen area will be on your right.