Although the existence of mood disorders was identified centuries ago, the present state of knowledge is unsatisfactory. This special issue of Archives of Suicide Research (ASR), the official journal of the International Academy for Suicide Research, presents the state of the science and collects new empirical data. Different aspects of suicidality in bipolar and bipolar spectrum disorders are outlined and the prophylactic aspects of pharmacotherapy are noted, especially the anti-suicide effect of lithium. A call for further study is, however, necessary.