ON A ROLL
The Tablinum of many well-to-do Romans had several scrolls ("volumina") . Reading material was very costly and scarce in Rome at first. Every roll was hand-written on papyrus, which was made from the pith of the papyrus plant native to the Nile valley. There were many grades of papyrus, the best coming from the center of the pith. This high quality grade was used for sacred documents and was called "hieratica". The lowest grades were used for fish wrapping or for toilet paper, but hopefully not the same sheet for both of those slightly less than noble uses. That leaves the middle grades for writing speeches and keeping accounts, which the Romans did on one side of the papyrus in little columns across the volumen.
INDELIBLE
To write on papyrus they used pens made from reed or feathers cut to a fine point, a practice that was still in use well into the 18th century. Ink was made from soot, resin, pitch and octopus ink. Sounds sticky, and certainly many an elegant toga was assigned to the rag bin with a tenacious stain, but it was the most interesting aspect in that, because of its inherent indelibility, many documents from Roman times have survived to this day. I don't think the ink your Bic could boast such staying power. Even on your shirt pocket.
MAKING AN IMPRESSION
Because paper was so expensive, an alternative was used for non-essential note-taking and the like. These were two pieces of wood coated with wax and fastened together with a hinge. Several of these wax tablets bound together formed a "caudex". This is the origin of our word "codex", the word we use for manuscripts, especially ancient ones.
The tablets were written on with a stylus, which was nothing more than a sharp wooden stick. I'm using a plastic stylus right now, as a matter of fact, to scratch on the surface of my Palm III. I just realized that the Palm looks a lot like a wax tablet and works on pretty much the same principle (or is it just that I'm being a little over-romantic?).