A review of the Coulomb explosion imaging method is presented along with a discussion regarding its use in determining the mechanism of the excited state double proton transfer (ESDPT) reaction of 7-azaindole dimer. A comprehensive discussion of the tautomerization process is outlined to fully explain the stepwise mechanism exhibited in our studies. Finally, recent comments are addressed relating to our technique and the interpretation of our results obtained by the method. Our findings are shown to be in excellent agreement with those of Zewail and co-workers who employed a different method of following the evolution of the stepwise ESDPT.