Interpreting focus again

How to respond to such a fine collection of commentaries which are, without exception, thorough, to the point, constructive, and full of suggestions for improvement? The best response by far would be a radical overhaul of the target article—but that is against the rules. The next-best thing would be a page-by-page discussion of each commentary separately—which the editor wouldn’t allow. So we have no choice but to make a selection of the many good points that have been raised, and hope against hope that we will manage not to distort them too much. The plan for the following discussion mirrors that of ‘Interpreting focus’ (IF). So we start with the main issue, concerning the association between focus and presupposition, then turn to focus particles, and conclude with a few remarks on it-clefts.