This Book Constitutes The Refereed Proceedings Of The Third International Symposium On Intelligent Data Analysis, Ida-99 Held In Amsterdam, The Netherlands In August 1999. The 21 Revised Full Papers And 23 Posters Presented In The Book Were Carefully Reviewed And Selected From A Total Of More Than 100 Submissions. The Papers Address All Current Aspects Of Intelligent Data Analysis; They Are Organized In Sections On Learning, Visualization, Classification And Clustering, Integration, Applications And Media Mining.