I am often asked for advice on how to avoid ambiguity in technical writing. One answer I can offer is the use of carefully controlled language, limited in vocabulary and structures, as described in Chapter 24. But such a form of ‘controlled’ English will not meet all our needs in writing technical texts. To communicate the shades of meaning and nuances of tone in subtle and complex description and argument, we need to use the full range of the resources of English. In such circumstances, I have to give a different answer to the question about avoiding ambiguity. The answer is: we can’t.