The intent here has been to present positive suggestions to help scientists develop or fine-tune their public speaking skills. Where "thou shall nots" appear, they are important because they reflect complaints heard repeatedly about public addresses in general and scientific talks in particular. Each "don't do this" is supported by a rationale and, in most cases, followed by recommendations on how to do it better.

Capturing, focusing and maintaining an audience's attention are the keys to giving a good talk in any situation. There are many references here to things that annoy, confuse and distract audiences because a room full of annoyed, confused or distracted people will not be receptive to or retain what you have to say. There are, of course, external factors that can affect the audience's concentration such as faulty audiovisual equipment or noise from outside the presentation room. The message here, however, is to point out some of the many things speakers do themselves, through inexperience or carelessness, that undermine their own talks and to offer insights on how to avoid those pitfalls.

Common sense plays an important role in preparing and giving a good scientific talk. Scientists have ample opportunities for comparison of good and bad talks. It is a serious matter to complain about the rambling, disjointed talk of a colleague and then give one yourself. The same is true of hastily prepared, illegible visual aids. You recognize what makes a talk good when you are in an audience, just as you recognize what makes a bad one. Take the time to develop the skills necessary to emulate the good ones and avoid duplicating the mistakes of the bad ones.

We hope this publication will assist with both efforts.