I joined a couple of his projects — helping him, in very minor ways, to edit the poems of William Collins and William Cowper — and then I went to work at the Morgan Library cataloguing its collection of British literary manuscripts. I, of course, believed that I had somehow earned all this, when, in fact, these were the benefactions of a professor and mentor who never breathed a word of his kindnesses.

Charles, who died last week at the age of 81, was a serious man, but gleeful, and all the more so because he was just slightly unaware of how amusing he could be. To see him in black tie at the opening of a Morgan Library exhibition — or, later, at the Frick Collection, which he led for a decade — was to see a man in rubicund humor. Academically, he was partly a product of the Boswell factory at Yale, the team of scholars editing the trove of James Boswell’s journals. His enduring literary project was editing the works of Cowper, one of the major minor poets of the late-18th century; a poet of deep existential crisis and, like Charles, a man of sensibility.

For all his ceremonial qualities, the Charles I knew — C.R., as he was called at the Morgan — was a modest man, delighted by the success of his students and perpetually flushed with enthusiasm.

We sometimes took the same train back to Princeton, and once, on the walk to Penn Station, I confessed that I was staggered to be working at the Morgan. I remember the look he gave me. It was more than complicity. It was an admission that he, too, was in love with his luck, still measuring day by day how far he had come to find himself at home in that glorious world of books and letters and drawings.