This book is focused on the development of non-steroidal anti-inflammatory drugs (NSAIDs); the biological target of these drugs is cyclooxygenase (COX) enzyme, which exists in two closely related isoforms viz. COX-1and COX-2. Based on the housekeeping functions of COX-1isoform and pathophysiological roles COX-2 isoform, the selective inhibition of COX-2 is desirable. NSAIDs like aspirin, ibuprofen, indomethacin, diclofenac, celecoxib, rofecoxib etc. exert their anti-inflammatory effects through the selective/non-selective inhibition of COX-1and/or COX-2 enzymes.