Rav Shmuel Leizer Volk was a Gaon Olam, graduate of Telz [the original, not nusach Cleveland or Chicago], who taught at YU for many years. Strangely, his bio doesn't appear on the bio page of YU Roshei Yeshiva. I have a theory as to why but would prefer not to share it.... [If you learn his sfarim you will figure it out].
I saw the following in his INCREDIBLE sefer שערי טוהר. Interesting.... וד"ל. [Maybe he didn't know].
