Part 1 Invited papers: issues in testing fast packet services over the broadband ISDN, M. Koblentz; testing in practice - OSI Test Center, M. Haulard la Briere; test selection based on ADT specifications, M.-C. Gaudel. Part 2 Theoretical foundations: the limited power of testing, M. Phalippou; on asynchronous testing, L. Verhaard et al; characterizing and ordering errors detected by conformance testing, K. Drira et al. Part 3 Conformance testing issues: on inconclusive verdict in conformance testing, S.T. Chanson and Q. Li; automated test case selection based on test coverage metrics, M. McAllister et al; diagnostic tests for single transition faults in non-deterministic finite state machines, A. Ghedamsi et al. Part 4 Test specification issues: an approach to the test of an ATM-based signalling application, M. di Concetto et al; an operational semantics for concurrent TTCN, T. Walter and B. Plattner. Part 5 Panel discussion on interoperabability testing: the silence of the LANs, D.J. Dwyer; interoperability testing panel minutes, J.-P. Favreau; position statements. Part 6 Panel discussion on test coverage and testability: summary of panel presentations and discussion, R.L. Probert. Part 7 Test selection - LOTOS: specification and derivation of OSI conformance test suites, T. Robles et al; interactive test generation from LOTOS specifications, S.P. van de Burgt et al; test system for a restricted class of LOTOS expressions with data parameters, T. Higashino et al. Part 8 Test selection and optimization: applications of sufficient conditions for efficient protocol test generation, A. Chung and D. Sidhu; a further optimization technique for conformance testing based on multiple UIO sequences, Z. Lidong et al; automated protocol conformance test generation based on formal methods for LOTOS specifications, A.R. Cavalli et al. Part 9 Multi-party testing experience: the IS-IS multi-party conformance test system, D. Tang et al; ISO conformance testing of the GSM mobile network system, R. Koester and M. Dicks; non-deterministic and fault behaviour, M.F. Witteman et al. Part 10 Panel discussion on GSM testing issues: position statements, Part 11 Test selection - non-determinism: test derivation from non-deterministic finite state machines, H. Kloosterman; generation of adaptive test cases from non-deterministic finite state models, P. Tripathy and K. Naik. Part 12 Overview of tool demonstrations.