This article investigates what might be characterised as "the forensic challenge" for criminal adjudication and clarifies its nature and scope.The "challenge"identified is complex,dynamic and multifaceted,encompassing a variety of issues and debates concerning the ways in which forensic science evidence is validated,generated,presented,tested,evaluated and utilised in criminal proceedings.Common law evidentiary principles governing the admissibility of scientific evidence and expert witness testimony are reviewed and the underlying assumptions and potential weaknesses of adversarial trial procedure are critically considered.The discussion is pitched at the genetic level of recurring intellectual puzzles,institutional design,regulatory frameworks,procedural structures and processes,macro-policy choices and methodological prescriptions,with the intention of making it relevant to an international audience.Aspects of the procedural law and adjudicative practice of England and Wales,and the regulatory context of UK forensic science,are offered as concrete illustrations with the potential for illuminating comparative extrapolation to other legal systems.In conclusion,the article draws out specific implications for Chinese scholarship,law reform and policymaking in relation to scientific and other expert evidence,and advances a bold suggestion for entertaining an unconventionally expansive conception of"forensic science" and,correspondingly,of the challenges it presents.