Superthin galaxies are bulgeless, late-type spiral galaxies seen edge-on. HI synthesis observations probe the kinematic structure of their interstellar medium. I shall present the results of high-sensitivity VLA observations of UGC7321, IC2233, UGC3697 and UGC10043. Two of these galaxies are rather isolated while the other two are the dominant members of small groups.
We have detected a pattern of « corrugations » in IC 2233, the first such detection in neutral Hydrogen in an external galaxy. UGC 3697, the « Integral Sign » galaxy shows a spectacular S-shaped bending that has been triggered by the passage of an intruder through its disk. UGC 10043, not quite a superthin galaxy, has presented us with an unexpected, rich interaction with a previously unknown companion which is reminiscent of the M51 system (the Whirlpool galaxy) « seen from the side. »