"Brilliant"
I have one of these and it's the best pepper mill I've ever had. I think the easiest way to describe how to open it is to hold the mill upside down by the main body and then with the other hand hold the ribbed section (between the main body and the grinding mechanism) and turn it anti-clockwise. The coarseness or fineness of the pepper can be adjusted by tightening or loosening the little black screw in the base.