This lecture introduces the player contract as the central legal instrument through which athletes enter, perform within, and exit professional sport. Rather than starting with clause-by-clause reading, the lecture begins with the threshold question that shapes everything that follows: what kind of legal relationship is being created, and what legal consequences flow from that classification? From there, it maps how player contracts operate in practice: how obligations arise (including through incorporation of rules and external instruments), why disputes typically emerge, and what happens when the relationship breaks down — termination, remedies, injunctions, player movement, and restraint of trade.