Substantial question of law allows appellate review, defining scope, formulation, multi-judge bench procedures and limitation exceptions. Appeals lie to the High Court from Appellate Tribunal orders when a substantial question of law is involved, except where the dispute concerns determination of duty rate or valuation for assessment. The High Court may formulate or take up substantial legal questions, determine issues not decided or wrongly decided by the Tribunal, and hearing is by a bench of at least two judges with majority decision rules; procedural rules and limitation periods apply, with the Code of Civil Procedure governing appeals unless otherwise provided.