n this present volume we have gathered eleven chapters in three main groups arranged by foundation type. The majority of offshore wind turbines constructed to date are supported by monopile foundations and this is reflected herein with six chapters addressing aspects related to their performance.The challenge facing designers is to determine the ultimate lateral resistance of these relatively rigid foundations; assess their response to cyclic loading and predict the dynamic response of the system across the life-cycle. As water depths and turbine sizes increase a move towards jacket structures may be required. These are usually supported either by axial loaded piles or suction caissons. For axially loaded piles methods to determine the effect of ageing in sand and to quantify cyclic loading events dominate current research in this field. Whilst pile foundations are a relatively maturetechnology the impact of the installation of suction caissonfoundations, particularly on the dynamic response of a windturbine, is considered in the work presented herein.