For all his vaguely taoist-sounding (but quite true) claims that you can't change the positive space of a shape without changing its negative space, he is insistent that working with an outline in the context of drawing the perimeter of a character or manipulating splines on a computer is somehow very different from working sculpturally with the form itself. To me the complementarity between the boundary and the shape itself is just as obvious as the complementarity between the inside and outside of the shape, so I don't really see what his point is.
Also his font, Renard, in which the book is set, has a really weird low-crossbar "t", which especially bumps up weirdly against the tiny-left-sidebearing "y", a common occurrence since the book mentions "type", "typographers", "typography", etc. about every other word. He slyly mentions in the colophon, "To purist eyes, some of the characters might seem out of balance with each other: but in text they work together happily and with assurance. [...] Renard captures the elusive, off-balance quality of its model: thus the name." Basically the standard post-modern refusal of criticism: but it's supposed to be bad!
Also went to a talk about typechecking C glue code in FFIs for O'Caml and Java. Kind of mysterious why he did a lot of things the way he did, but apparently his tool found a lot of previously unknown bugs, so good for that.