A Roman lyric poet of the first century BC. He was the son of a fairly well to do merchant. His poetry is known for its urbane and polished nature. His poems deal primarily with love and hate. Early in his career he writes love poems to the married woman with whom he is having an affair (he calls her Lesbia). However after she rejects him his poems become rather mean spirited for instance:

Come here, nasty words, so many I can hardly
tell where you all came from.
That ugly slut thinks I'm a joke
and refuses to give us back
the poems, can you believe this shit?
Lets hunt her down , and demand them back!
Who is she, you ask? That one, who you see
strutting around, with ugly clown lips,
laughing like a pesky French poodle.
Surround her, ask for them again!
"Rotten slut, give my poems back!
Give 'em back, rotten slut, the poems!"
Doesn't give a shit? Oh, crap. Whorehouse.
or if anything's worse, you're it.
But I've not had enough thinking about this.
If nothing else, lets make that
pinched bitch turn red-faced.
All together shout, once more, louder:
"Rotten slut, give my poems back!
Give 'em back, rotten slut, the poems!"
But nothing helps, nothing moves her.
A change in your methods is cool,
if you can get anything more done.
"Sweet thing, give my poems back!"

The translation is Copyright 1995, by Richard Bullington-McGuire who is a nice guy and has allowed me to reproduce it here under a Creative Commons Attribution + Noncommercial licence. CST Approved See:
http://www.obscure.org/obscene-latin/catullus-42.html

The vulgarity of some of his work is rather striking. In addition to lambasting Lesbia for rejecting him he writes entire poems threatening to sodomise certain people who have cheated him or who have critisized his work.
However he can also be quite introspective at times:

I hate and I love. How can this be, you ask in vain.
I know not. But I feel it to be so, and am wracked with pain.

He was one of the first poets to make really explore the use of the latin language for poetry (as opposed to greek).
We are told that Catullus "died of love" whatever that means.