Acknowledgements

My first thanks are due to Frank Thomas and Jeremy Laffan since both spent much time explaining the domain and its documentation. Frank provided relentless assistance and expertise and opened many doors. Jeremy took the time to read through and comment on the first draft of this thesis.

The other members of the oil system group in service engineering in the customer support department at Rolls Royce Commercial Aero Engines ltd in Derby, Angus Abrahams, Simon Beevers, Graham Briggs, John Heathcote, Alan Steele, and Chris Timm, were equally helpful. At the department of Visual Communications, Ted Bardgett, Mark Johnson, Keith Lycett, and Andy Smith explained the design of system diagrams. I received help from many other people at Rolls Royce who are too numerous to mention. I would like to single out John Buckland, then Manager of Visual Communication, who arranged my first one week attachment from which the rest developed.

My research also involved visits to airlines and service providers.  I wish to thank Andy Kitney and David Smith of British Airways, Mr Orlowski, Mr Groth and Mr Goll of Lufthansa, Horst Ottow of NAYAK Aircraft Service, and Ron Cook of SUPAIR GmbH Airline Support Service.

I also thank colleagues and students at Coventry University, particularly all members of the Visual and Information Design (VIDe) research centre. Jen Conolly, Claire Elkington, Sue Flynn, Helen Orr, and Simon Turner helped evaluating the cinegram.  Sam Porter and Perry Hinton advised on methodological issues. Don Hinson helped developing the questionaire and enticed his students to volunteer for the evaluation.

I thank John Vince, Don Hinson and John Lindsay for their constructive advice and critique during my meandering research process. The contact with John Lindsay's work in particular has moved this study from concerns with techniques and tools to involvement with a professional context and its substantive problems.

Finally I want to thank my director of studies, Clive Richards, for his support, comments and critique, and particularly for his great patience which gave me the essential time for the grounded theory process and the maturation ot its outcome.