Book excerpt: There are many issues of arbitral practice that remain largely unaddressed, or very poorly addressed, in the sources to which tribunals and counsel conventionally turn for procedural guidance: the arbitration agreement, the lex arbitri and rules of procedure. This book brings together the most frequently recurring of such “twilight” issues—so-called because all participants in the arbitral process, when facing them, find themselves “in the dark”—showing in each case where it is best for arbitrators, counsel, and parties to look for solutions offering logic, certainty and predictability. The issues ably covered by the author include, among others, the following: Is a non-signatory bound by or entitled to invoke an arbitration agreement? When may res judicata or collateral estoppel subject? Should a tribunal issue an anti-suit injunction? When may a tribunal treat as mandatory a law other than the chosen one? On what basis may a witness invoke testimonial privilege? When may a tribunal sanction counsel for what it considers misconduct? By what standards is a determination of corruption to be made? How should a tribunal determine the interest rate applicable to an award? On what basis are costs to be allocated? Examining in turn the guidance that may be provided by normative sources—national law (and if so, which one?), simple exercise of good judgment, or “international standards” derived from soft law, arbitral jurisprudence, international law, and scholarly and professional commentary—the analysis clearly shows how, when conventional sources of legal guidance are unavailing, decisions on important matters of arbitral practice and procedure are best made. The book will prove of major relevance and value to any and all stakeholders in the international arbitral process, whether commercial or investor-state.