Americans began chewing gum long before 1850, scraping resin from spruce trees, removing any bits of bark or insects and chewing the finished product. Commercially-made gum was of limited availability and came in three types--tree resin, pretroleum-based paraffin and chicle-based--the latter, a natural latex, ultimately eclipsing its rivals by 1920. Once considered a women-only bad habit, chewing gum grew in popularity and was indulged in by all segments of society. The gum industry tried vigorously to export the habit, but it proved uniquely American and would not stick abroad. This book exam