Cover photograph (Copyright © 2007, American Society for Microbiology. All Rights Reserved.): Giardia intestinalis trophozoite showing kinesin-13::green fluorescent protein localization (green), microtubule structures (anti-|ga-tubulin immunostaining, red), and DNA staining (4′,6′-diamidino-2-phenylindole, blue). The sole giardial kinesin-13 protein localizes primarily to the distal flagellar tips, the median body, cytoplasmic regions of several axonemes (primarily the anterior and posterolateral), and the kinetochores of the mitotic spindle (not shown). Kinesin-13 regulates microtubule dynamics in these various and diverse microtubule arrays. (See related article on page 2354.)