Clues on the Structure and Composition of Galactic Disks from Studies of "Superthin" Spirals: the Case of UGC3697

We summarize results from an HI+optical imaging study of the ``Integral Sign'' galaxy, UGC3697. UGC3697 is a low-mass, Sd spiral that exhibits a ``superthin'' disk morphology despite a prounced gasous and stellar warp. Our new observations show evidence for a recent minor merger in this system that could account for its large-scale warp and a number of other properties of this galaxy. We speculate that UGC3697 has been caught in a rather short-lived dynamical state, and may soon undergo significant structural and morphological changes.