The NATO Advanced Studies Institute series "Targeting of Drugs" was originated in 1981. It is now a major international forum, held every two years in Cape Sounion, Greece, in which the present and the future of this important area of research in drug delivery is discussed in great depth. Previous ASIs of the series dealt with drug carriers of natural and synthetic origin, their interactions with the biological milieu, ways by which milieu interference is circumvented, approaches to carrier design or modification that contribute to optimal carrier function, and, more recently, with strategies for gene and oligonucleotide delivery in therapy The present book contains the proceedings of the 9th NATO ASI, "Targeting of Drugs: Strategies for Stealth Therapeutic Systems", held in Cape Sounion during 24 June -5 July 1997. As the title implies, the book deals with a variety of approaches to evade the reticuloendothelial system and thus extend the circulation time of a variety of delivery systems including polymers, biopolymers, liposomes, and other nanoparticles or microparticles. We express our appreciation to Mrs. Concha Perring for her assistance with the organization of the AS!. The ASI was held under the sponsorship of NATO Scientific Affairs Division and supported by Sequus Pharmaceuticals (Menlo Park, CA, USA), The Liposome Company (Princeton, NJ, USA), NOVO Nordisk (Bagsvaard, Denmark), NeXstar Pharmaceuticals (Boulder, CO, USA), Gene Medicine (Houston, TX, USA), Pfizer Ltd (Sandwich, Kent, UK), Merck (Rahway, NJ, USA), and Biovation Ltd (Aberdeen, UK).