This volume contains reviews which are based on a symposium, given th at the 30 meeting of The Phytochemical Society of North America, held at Laval University in Quebec City, Canada on August 11-15, 1990. During the past two decades, there have been major new developments in methods which can be applied toward the isolation, separation and structure determination of complex natural products. Therefore, the topic of this symposium, Modem Phytochemical Methods , is a very timely one. The organizers of the symposium recognized that it would not be possible to cover in detail all new advances in phytochemical methodology. It was therefore decided to emphasize general reviews on recent developments of major separation techniques such as high performance liquid chromatography as well as supercritical fluid chromato graphy. In addition, advances in commonly used structure determination methods, mainly NMR and MS, are reviewed. Other topics include methodo logies of micro-sampling for isolation and analysis of trichome constituents as well as recent breakthroughs on biosynthetic studies of monoterpenes using enriched basal cells of trichomes. The volume concludes with a review of quantitative structure-activity relationship (QSAR) studies of biologically active natural products. In Chapter I, K. Hostettmann and his colleagues give a general review of recent developments in the separation of natural products with major emphasis on preparative separations of biologically active plant constituents. The authors present a comparison of droplet countercurrent chromatography (OCCC) with the highly rapid and more versatile centrifugal partition chromatography (CPC).