I was very sad to hear about Alan Krueger's untimely and tragic death.
I didn't know him personally, but was only two degrees of separation away by multitudinous pathways (if we define knowing someone directly as one degree of separation).
On a professional note, I was intrigued and influenced by Krueger's minimum wage work with David Card, which I first read - fittingly enough - when I was on the verge of leaving the University of Chicago for NYU in the mid-1990s. To economists, part of the interest lay in the use of well-chosen natural experiments to raise questions, the answers to which had unduly been taken for granted (and left unchallenged by reason of publication bias in favor of positive findings). But for me, the main interest lay in its potential theoretical and policy implications.
I found the Card-Krueger work illuminating with respect, not just to minimum wages' potential employment and broader wage effects in particular, but also the more general need to go beyond "Econ 101-ism" and think hard about how particular markets' - especially labor markets' - odd features can lead to non-neoclassical results. (This even before the full rise of behavioral economics, which plays an important, albeit only partial, role in explaining how Card-Krueger outcomes could come to be.)
Throwing in as well my interest in the interrelationships between various formally distinct, but substantively overlapping, types of rules (e.g., minimum wage versus cartelization versus mandate versus EITC versus negative income tax), I wrote here about all of the above, including the Card-Krueger work. I probably still agree with most, though perhaps not all, of what I wrote there more than 20 years ago.
Krueger continued to do important work after his minimum wage research, in addition to being a great public servant in two Administrations.