The mitotic spindle of the budding yeast Saccharomyces cerevisiae will prob
ably be the first such organelle to be understood in molecular detail. Here
we describe the mitotic spindle cycle of budding yeast using electron-micr
oscope-derived structures and dynamic live-cell imaging. Recent work has re
vealed that many general aspects of mitosis are conserved, making budding y
east an excellent model for the study of mitosis.