Comments on some of Wolf's research: first studies of coherence in the mid-1950s; lasers and the problem of complete coherence; holography; global coherence; the structure of laser light in the focal plane of lenses; coherence in the space-frequency domain; the nature of scientific progress. Also includes discussion of the social circumstances of his research: funding arrangements; consultancies; scientific contacts; the controversy between Glauber and Wolf, Mandel, and Sudarshan.