'nle 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. Five previous ASIs of the series dealt with drug carriers of natural and synthetic origin, their interaction with the biological milieu, with ways by which the latter influences such interaction and strategies by which milieu interference curtailing the ftmction of drug carriers is circumvented or relieved. 'nle present book contains the proceedings of the 6th NATO ASI "Targeting of Drugs: 'nle nias who, as chairperson of the Local Corrmittee, contriruted to the success of the Institute. 'nle ASI was held under the sponsorship of NATO Scientific Affairs Division and co-sponsored and generously financed by SmithKline Beecham Phannaceuticals (King of Prussia). Financial assistance was also provided by Syntex Laboratories Inc. (Palo Alto), Syntex Research (Palo Alto) and pfizer Central Research (Sandwich).