From the reviews:
"For the 2 volumes of the Selecta, 59 papers of P.D. Lax were chosen and reprinted in order to represent his main achievements. The editors qualify the papers as ‘classics’ and state: ‘their impact continues to be felt both explicitly and implicitly in current research’. ... let me mention that the two Selecta volumes contain further highly original ideas ... ." (Norbert Ortner, Mathematical Reviews, Issue 2006 k)
"Since Peter Lax was chosen as the recipient of the 2005 Abel Prize, it’s hardly necessary to say that his work is important. Libraries should consider his Selected Papers an essential acquisition. ... This second volume includes many papers on scattering theory, a few on functional analysis, and several others ... under ‘analysis’ and ‘algebra’." (Fernando Q. Gouvêa, MathDL, October, 2005)