Jan's Four Knights
If you're a 1.e4 e5 player, you'll soon realize that the Four Knights, 1.e4 e5 2.Nf3 Nc6 3.Nc3 is a popular and annoying weapon at White's disposal.
You need to learn how to deal with it, whether your weapon of choice against the Spanish (Ruy Lopez) is the Marshall, the Berlin, or the Petroff.
Grandmaster Jan Gustafsson teaches you how to react to 3.Nc3 in the most ambitious manner. This is essential viewing if you play either side of the Four Knights.