This document discusses the legal standard of non-obviousness for patents under 35 U.S.C. § 103. It outlines key Supreme Court cases that have interpreted and refined the standard over time, moving away from a rigid "teaching, suggestion, or motivation" test established by the Federal Circuit court. The KSR v. Teleflex case in particular reaffirmed that common sense and obvious-to-try modifications can support a finding of obviousness. Secondary considerations like commercial success must also be considered in determining obviousness.