This project - led by Will Jennings and Christopher Wlezien - brings together what is believed to be the largest international collection of election intention polls. The dataset includes over 30,000 pre-election polls in national elections from 45 countries since 1942 to the present day. The data collection is part of their research into how voters' preferences evolve over the election cycle - across different political and electoral systems. To date, their research has produced articles in the American Journal of Political Science, Electoral Studies and Nature Human Behavior. More articles and a book are underway. Jennings and Wlezien continue to expand the dataset, including more countries and elections as they locate new polls. They welcome and are pleased to acknowledge any additional research data or corrections to any of the reported findings.