Sam Lee (defendant), a California resident, and Milton Klein (defendant), a New York resident, each saw magazine advertisements, while in their respective home states, about computer software. The software was sold by Michael Chalek (plaintiff), the sole proprietor of a business in Illinois. Lee and Klein each placed telephone orders for the software, which was delivered to them in California and New York, respectively. Both buyers paid by check. Neither negotiated the terms of the sale or traveled to Illinois for the purpose of inspecting Chalek’s facilities or otherwise. Lee and Klein were both dissatisfied with the software. They each sent it back to Chalek and stopped payment on their checks. Chalek brought separate lawsuits against Lee and Klein, in Illinois state court, for nonpayment. The trial court dismissed both suits for lack of personal jurisdiction. Chalek appealed.