Neil O`Brien, who recently passed away, was a well-known figure in the field of quiz mastering. This means that he gained popularity for his expertise in hosting and conducting quizzes. As a quiz master, O`Brien would have been responsible for organizing and presenting quiz competitions, asking questions, and managing the flow of the event. This role requires strong knowledge in various subjects, such as history, science, sports, and current affairs, as well as excellent communication skills to engage and entertain participants.

It is important to note that the other options listed do not accurately represent Neil O`Brien`s profession. He was not a journalist, which refers to someone who reports news and events. He was not a billiards player, who participates in the sport of billiards. And he was not a dramatist, which typically refers to a playwright or someone involved in creating and producing works of drama.

In conclusion, Neil O`Brien was renowned as a quiz master, using his expertise and skills to entertain and challenge participants in quiz competitions.