There's an excellent tribute on Curt Evans' blog to Jacques Barzun, who has died at the ripe old age of 104. Curt says most of the things I'd like to mention about Barzun,a crtic of whom I first became aware through reading Julian Symons' Bloody Murder. Symons disagreed with Barzun about many aspects of crime fiction, but I'm certain both men had a great deal of respect for each other.
A Catalogue of Crime is a fascinating reference work, and long ago I invested in both editions. Barzun and his collaborator Taylor comment on many books that were otherwise ignored in reference works about detective fiction, and I suspect they would be delighted to know that "forgotten books" of the type they enjoyed are finally emerging from obscurity thanks to digital publishing and internet commentaries. It is, mind you, an idiosyncratic text, and like all reference books it contains the occasional howler (such as locating Knutsford in Ireland). But it's a terrific book to dip into, and one I strongly recommend.
One does not have to agree with all (or even most) of what Barzun wrote about the genre to recognise the value and importance of his contribution to crime fiction criticism. His love of classic detective fiction became unfashionable, but - even though I'm more in the Symons camp in many ways - I think that the best of the books that he lauded will endure for as long as crime fiction is read, and his acute assessments of many of those books will remain indispensable not only for confirmed Golden Age fans but also for others who come to recognise the merits of the classic mystery, as well as its potential limitations - a group that is, I sense, growing quite rapidly, something of which Barzun would surely have approved.