Underlining can serve the same function as italicizing.
You can underline book titles, emphasized words, and so on; it’s
a handy way to work when hand-writing text. But italicizing is preferable
to underlining.
Acceptable: Uncle
John’s Bathroom Reader is my favorite book.
Desirable: Uncle
John’s Bathroom Reader is my favorite book.
Whatever you do, be consistent. If you choose to italicize
(which you should), don’t underline at all; if you choose to underline
(which you shouldn’t), don’t italicize at all.
