What is Junjou Romantica?

Junjou Romantica is an on-going BL series written by Nakamura Shungiku which is currently being published in the magazine Tres Tres. It contains three different couples in three different arcs: Junjou Romantica: the main couple Usami and Misaki, Junjou Egoist: Hiroki and Nowaki, and Junjou Terrorist: Professor Miyagi and Shinobu. They are collected and published together under the name Junjou Romanica in tankoubon form.