Opera may be hot again, but precious few American cities can boast of having a truly world-class opera company. One of the lucky few is Houston, where the Grand Opera marked its 50th birthday last weekend, and Joshua Kosman says that you don’t have to look very hard to see how the company has achieved its success. “To speak of the Houston Grand Opera is to speak of David Gockley, the visionary general director who has led the company since 1972 and made it what it is today.” Gockley will shortly be leaving Houston to take up the reins of the San Francisco Opera, and Kosman says that the Bay Area can realistically hope for a newly reinvigorated company under his leadership.