Title: will be set by the publisher Editors: will be set by the publisher EAS Publications Series, Vol.?, 2008 A SURVEY OF MULTIPLE PLANET SYSTEMS

Abstract. To date, over 30 multiple exoplanet systems are known, and 28 % of stars with planets show significant evidence of a second companion. I briefly review these 30 systems individually, broadly grouping them into five categories: 1) systems with 3 or more giant (M sin i> 0.2MJup) planets, 2) systems with two giant planets in mean motion resonance, 3) systems with two giant planets not in MMR but whose dynamical evolution is affected by planet-planet interactions, 4) highly hierarchical systems, having two giant planets with very large period ratios (> 30: 1), and 5) systems of “Super-Earths”, containing only planets with (M sin i < 20M⊕). It now appears that eccentricities are not markedly higher among planets in known multiple planet systems, and that planets withM sin i < 1MJup have lower eccentricities than more massive planets. The distri-bution of semimajor axes for planets in multi-planet systems does not show the 3-day pile-up or the 1 AU “jump ” of the apparently-single planet distribution.