[WT Sharpe]

In non-fictional works, sometimes I underline passages in order to later quote them in relevant discussions, and sometimes I will underline passages simply because I feel they make an important point or contain information someone else could be interested in. Often I will annotate a passage to add my own thoughts upon the subject under discussion, even if it's just to note my agreement or disagreement with the author's position.

In fictional works, I will often find a turn of phrase that I particularly like and will copy it simply as a way of encouraging myself to discover similar fascinating adornments for my way of speaking.

When I come across an unfamiliar word I'll look it up in the Kindle's dictionary and copy it as a way of building my vocabulary.

But the biggest reason by far, whether the book is fiction or non-fiction, for underlining and notation is as an aid to memory.

Prior to owning an e-reader, I would sometimes find myself the object of a bit of good-natured ribbing over my habit of constantly high-lighting and notating everything I read. Two of the comments I heard most ran along the lines of, "Tom, you DO know that's not a coloring book, don't you?" and "Tom can't read without a pen in his hand!"

I wouldn't consider buying a reader that didn't have a keyboard or virtual keyboard.