IF YOUR CLIENT is a dedicated outdoorsman, how do you design an indoor space for him? James Huniford, the interior designer, recently addressed this issue in a 2,200-square-foot Manhattan apartment.

Mr. Huniford's client, a commodities trader, is a Type-A-plus person (he is currently training for a "persistence hunt" in Africa). At home, what he discussed with the designer was the need for "a retreat," as he described it, "a place that was an oasis, that had an organic and natural calming feeling...