Homogeneously catalyzed reactions suffer from one big disadvantage: separation of the catalyst from the products is complicated (and expensive) and catalyst recycling is often sub-optimal. This book describes homogeneously catalyzed reations with a)organometallic complexes as catalysts in b)aqueous (and other) biphasic systems. The advantage of this method: One can separate the products (organic phase) from the catalyst (aqueous phase) by simply decanting the mixture. This saves time, money and waste! No wonder that it took only ten years from the first discovery of this method to industrial implementation of a 100 000 t/year plant. An international authorship contributed to this book and gave first-hand reports on their work. One focus is the hydroformylation process - the first industrial large scale aqueous biphasic catalytic process.