Grilled Swordfish with Rosemary Mayonnaise

There are as many accompaniments to grilled swordfish as there are combinations of ingredients, but the most successful in my restaurants have involved some form of ratatouille: eggplant either pureed and made spicy with coriander or roasted with garlic and herb oil, or mixed summer squash ragouts with butter and powerful fresh herbs. Because of its richness, swordfish certainly needs and can handle strong herbs, and I especially like rosemary with it. It is great with tapenade (a puree of