A discussion of the difficulties of measuring adhesion. Results obtained by various methods are critically considered in the light of theoretical and other estimates of the magnitude to be expected. New ideas on scratch testing are presented and some of the difficulties associated with this method are discussed. For measuring the adhesion of thin films, it still remains as one of the most successful methods and some of the more recent results obtained in this way are presented. In the case of metal films on polymer surfaces, there is increasing evidence of charge transfer across the interface and electrostatic bonding may make a significant contribution to the measured adhesion.