Alan Mackay, J.D. Bernal, and the rewriting of the book of crystallography

Abstract Musing over half a century of interactions with Alan Mackay, a rich array of thoughts on past occasions emerges—personal as well as professional—some serious, some playful, and some approaching the bizarre. Browsing through a few of these thoughts, I attempt to illustrate some of those aspects of Alan that have demonstrated to me not just his broad, radical intellectual imagination, but also his generosity and humanity, as well as how the environment of the Birkbeck Crystallography Department and his links with J.D. Bernal were instrumental in enabling his fertile mind to flourish.