2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/63301This is a partly expository, partly new paper on sup norm estimates of eigenfunctions. The focus is on the quantum completely integrable case. We give a new proof of the main result of our paper ``Riemannian manifolds with uniformly bounded eigenfunctions' (Duke Math J. 111 (2002), 97-132), based on the analysis of quasi-modes and Birkhoff normal forms. We also discuss related issues of resonant normal forms and tunnelling between tori.A conference talk at the June 2001 Mt. Holyoke conference in harmonic analysisAnalysis of PDEsMathematical Physics58J50text