SALZBURG, Austria – If the festival has a number-one star, it is probably Thomas Hampson, the American baritone (who has long made his home in Austria). In a typical summer, he is all over this town: speaking before groups, singing with orchestras, giving recitals, appearing in operas. He may have earned the title Mr. Salzburg.

But this has been a trying month for Mr. Hampson: Allegations of financial impropriety have been made against his family and him in the Austrian press. Mr. Hampson has hotly denied those allegations, vowing to smash them and their disseminators. Through this ordeal – and Mr. Hampson has made clear it is that – he has sung superbly.

Last Thursday night, he gave a recital, dedicated to “forbidden composers,” those whose music was banned or suppressed in the Third Reich. Tonight, he will give another recital, in the company of three other singers – the theme is the same. The Salzburg Festival has been honoring such composers for the last several seasons. And on Mr. Hampson’s Thursday-night program were songs of Mendelssohn, Meyerbeer, Zemlinsky, Zeisl, Schonberg, Berg, and Mahler. All of those composers were Jewish – religious belief aside, they were certainly considered so by Nazis.

The Grosser Saal of the Mozarteum was packed to overflowing; in fact, patrons filled either side of the stage. Mr. Hampson began with Mendelssohn’s “Auf Flugeln des Gesanges”: little, lovely, evergreen. After a second Mendelssohn song – “Altdeutsches Fruhlingslied” – he sang three by Meyerbeer, all in the German language, much different from the Italian songs of Meyerbeer that Cecilia Bartoli had presented earlier in the week. The Italian ones are pleasant; the German ones have a stronger claim to art.

We then had six songs of Zemlinsky, whose music has made a comeback in the last decade or so. This is in part thanks to the conductor James Conlon, who has recorded many Zemlinsky works for EMI. Erich Zeisl (1905-1959) is not so well-known as these other composers, but Mr. Hampson was right to include two of his songs. One of these was “Die Nacht bricht an,” which is sort of woozy and hazy – it is also enchanting.

Following the Zeisl were three songs of Schonberg, which required some rhapsodic piano playing. Mr. Hampson had with him his regular accompanist, Wolfram Rieger. Mr. Rieger barely put a foot wrong, all night long. In more than one review, I’ve written, “I would like to hear Mr. Rieger play a solo recital.” The pianist’s performance on Thursday night only increased that desire.

After intermission, Mr. Hampson offered four songs that Berg wrote as a teenager – Romantic and earnest songs. And then two more of Schonberg, including the well-loved “Ewartung.” And, to close the program, the “Ruckert Lieder” of Mahler. You rarely hear the “Ruckert Lieder” sung with piano, but, given Mr. Rieger’s presence, you hardly missed an orchestra. It happens that a singer can do these songs in any order he wishes, and Mr. Hampson chose to begin with the quick one, “Blicke mir nicht in die Lieder!” He also chose to omit one of them, “Liebst du um Schonheit” – some think that a man ought not to sing this song, leaving it to women.

But hang on, Mr. Hampson sang an encore – and it was “Liebst du um Schonheit.” How did he sing it? I once heard him say in a master class that this is a happy song, and must be sung happily. He had an excellent argument. But, no matter what the words say – and no matter what intellect tells you – I still hear a vein of melancholy or wistfulness in Mahler’s music. And so musical debate continues.

After the encore, Mr. Hampson gave a little speech saying that never again should music be forbidden, and acknowledging a couple of people key to his project. Then he bade goodnight.

I have never heard him sing better, over the years. He was at the top of his game. Mr. Hampson has the essential ingredients of voice, technique, and smarts. That voice was a wonder, and it issued some of the sweetest baritone high notes you’ll ever hear. The lowest notes were more suspect – somewhat lacking in volume and body. This mattered almost not at all. And that technique is important because it allows Mr. Hampson to interpret a song the way he wishes. A singer may have laudable notions in his head, but, without vocal technique, he may not be able to act on them. Mr. Hampson faces no obstacles.

As to smarts: Mr. Hampson is a thoughtful and analytical guy, and I sometimes fear this works against him. He is subject to overinterpreting, or over-poetizing, if you will. I often say, “Give me a dumb singer, who’ll let the music and the text speak for themselves.” To cite one instance from Thursday night: Mr. Hampson gave the first line of (Mahler’s) “Ich atmet’ einen linden Duft” a serious ritard. I think that is much better off straight, certainly straighter. And I wish he’d let “Ich bin der Welt abhanden gekommen” (also Mahler) simply unfold; the best thing you can do for it is get out of its way.

But this is too picky: On balance, Mr. Hampson was utterly persuasive, giving a recital that should serve as a model. His programming was good and interesting, yes – but without execution, we just have musicology.