J. G. MCVIE The impact of therapy on one subset of lung cancer, the "small cell" type has been significant and lasting. The reality of cure for even a fraction of patients with this disease has caused reverberations in the pathology lab where the responsibili. '~y and challenge of diagnosis of this vital sub group lies. No less dramatic has been the discovery that the cell types of lung cancer have recognisable growth characteristics in serum free culture, they are recognisable by patterns of markers and some produce growth factors which autoregulate their eventual fate. Many of the discoveries from the biological studies have impacted on the pathologist in the form of disturbing evidence for a single stem cell origin for all the cell types of lung cancer and in the shape of new facilitation in diagnosis by appli­ cation of immunoperoxidase techniques. Monoclonal antibodies raised against oncogene products, growth factor receptor sites, "bystander" cell membrane proteins can all be applied to cytology specimens and frozen or paraffin fixed tissue sections to aid diagnosis and some can be used in sequential serum assay to monitor therapy and predict prognosis. Adding to these extraordinary tools, the sophistication of electron micro­ scopy and immuno-electrcn microscopy, new techniques for preparation of tissue and novel methods for studying vital cells in "kinesis", you sense the flavour of the future of lung cancer which is captured in this book.