Thirty years after treatment of the first human with botulinum toxin, application of the drug has expanded to an extraordinary variety of conditions. I did not initially anticipate use in the gastrointestinal tract, the bladder wall, pathological sweating, reduction of saliva and tears, and surely not widespread cosmetic use. Yet, a look back at Kerner's descriptions of botulism shows us that each of those areas, even the flat and featureless face, was impacted by the toxin. Use in migraine and pain disorders is entirely new and unpredicted; surely further valuable uses of botulinum toxin and of new drugs based on the toxin molecule will continue to emerge.

The expert authors of this volume, several of them originators of the applications described in their particular chapters, carry to us and to our patients masterly teaching of the techniques for botulinum toxin's safe and effective use.