If you are writing an essay do you underline, use quotation marks or italicize the book title?

If you
are using a word processor you can and should italicize book titles. However, if you are using a
typewriter, I don't see how you can use italics. Before word processors
came into common usage, it used to be the standard practice to underline book titles when
typing. This indicated that these titles should be in italics if the manuscript was published in
a book, magazine, or newspaper. If you are writing something in longhand you should also
underline book titles, but I don't see how you could have any other choice, unless you happen to
be artistically gifted and can make your handwriting look like italics when you want to. There
may be some typewriters which allow you to switch from regular typeface to italics, but I have
never seen one. No doubt the IBM Selectrics could be used to type book titles in italics if you
switched from one ball to another and then back again, but that seems awfully
time-consuming.