Half a century ago, thalidomide was developed as a sedative drug and was wildly used over 40 countries. However the drug has serious birth defects such as amelia and phocomelia. Now thalidomide is regarded as a clinically effective drug and used for the treatment of multiple myeloma under strict controls. The direct target of thalidomide had been a long-standing question. We identified cereblon as a primary direct target protein for thalidomide teratogenicity using new affinity bead technology in 2010. In this review, we introduce an overview of thalidomide teratogenicity, a story about how we identified cereblon, and recent advances in cereblon studies.