Designed by Josh Frankel, copyright Binary Arts 1998, made in China.
(plastic, 3.6 inches diameter by 5/8 inches thick)

The puzzle has a circular track that can hold 9 discs and a track across the center that can hold two additional discs. The track across the center is actually Y-shaped, but this is just to make the piece fit well. The basic operations are to rotate the circle of discs, or to move a disc into or out of the center track (so there are a total of 10 discs and a gap, and at any time the circle has 10 discs and center track 1 disc, or the circle has 9 discs and the center track 2 discs). The goal is to mix up the puzzle and then restore it to the solved position where the discs numbered 1 to 9 are in numerical order around the circle and the white disc is in the center. Jaap's Page presents two different solution methods. A much easier puzzle in this theme is Diamond Bob's Billiards.

Further Reading
Jaap's Page, from: http://www.jaapsch.net/puzzles/nineball.htm