Eschewing the kind of self-referential pomposity that most anchors thrive on , '' A Tuesday With Morrie '' allows Mr. Koppel to take another look at a once-unknown man , Morrie Schwartz , a Brandeis University professor who in 1995 allowed '' Nightline '' to document the last year of his life as he battled A.L.S . , or Lou Gehrig 's Disease .