Fair warning: If I give a talk --- at your conference, lecture series, meeting, whatever -- and you ask me for "a copy of my presentation" I'm probably going to refuse. It isn't personal and I'm not trying to be difficult. It's just that I have nothing that I can sensibly give you.

Many speakers these days make their visual aids available, but I don't. I don't always use any, but even when I do, they just aren't intended to be comprehensible outside the context of my talk. Creating slides that can serve double duty as props for my talk and as a stand-alone summary of the content is, I must confess, a talent that lies beyond the limits of my ability. Fortunately, when I give a talk I've usually also written something about the subject too, and almost all my papers are freely available to all. Unlike my slides, I try to write in a way that makes sense even without me standing there explaining things while you read.

"Presentation software" like PowerPoint (and KeyNote and others of that ilk) has blurred the line between mere visual aids and the presentations themselves. I've grown to loathe PowerPoint, not because of particular details that don't suit me (though it would be nice if it handled equations more cleanly), but because it gets things precisely backwards. When I give a talk, I want to be in control. But the software has other ideas.

PowerPoint isn't content to sit in the background and project the occasional chart, graph or bullet list. It wants to organize the talk, to manage the presentation. There's always going to be a slide up, whether you need it there or not. Want to skip over some material? OK, but only by letting the audience watch as you fast-forward awkwardly through the pre-set order. Change the order around to answer a question? Tough -- should have thought of that before you started. You are not the one in charge here, and don't you forget it.

When I give a talk, I like to rely on a range of tools -- my voice, hand gestures, props, live demos, and, yes, PowerPoint slides. I tend to mix and match. In other words, from PowerPoint's perspective, I'm usually using it badly, even abusively. I often ignore the slides for minutes on end, or digress on points only elliptically hinted at on the screen. When I really get going, the sides are by themselves useless or, worse, outright misleading. Distributing them separately would at best be an invitation to take them hopelessly and confusingly out of context, and at worst, a form of perjury.

Unfortunately, "PowerPoint" has become synonymous these days with "presentation", but I just don't work that way. Maybe you don't work that way either. There's no one-size-fits-all way to give a talk, or even a one-size-fits-me way. So when I'm asked for my slides, I must politely refuse and offer my papers as a substitute (an idea I owe to the great Edward Tufte).

Fortunately, I'm senior enough (or have a reputation for being cranky enough) that I can usually get away with refusing. Sometimes, though, when pressed hard, I'll give in and send these slides [pdf].


Addendum 26 November 2010: This post sure has struck a (perhaps dissonant) chord somewhere, especially for a long holiday weekend. I'm grateful to all who've emailed, blogged, and tweeted.

Several people have thoughtfully suggested their favorite alternatives to PowerPoint (Prezi seems to be the popular choice), which I'll certainly check out. And for the record, yes, I know about (and use when I can) PowerPoint's "presenter" mode, which improves control over the audience display. Unfortunately, both alternative software and presenter mode, while improvements, are at best unreliable, since they assume a particular configuration on the projecting computer. It often isn't possible to project from a personal laptop (especially in conferences run on tight schedules), leaving us at the mercy of whatever is at the podium. And that often means PowerPoint in single-screen mode.

In any case, while there is certainly room for me to improve my mastery of PowerPoint and its alternatives, this wouldn't solve the basic problem, which is that, in my case at least, my slides -- when I use them at all -- aren't the content. They won't help you understand things much more than would any of the other stuff I also happen to bring up on stage with me, like, say, my shoes (which you can't have, either). But you're welcome to my papers.