Van Loon and Cronin

Browsing in Nabokov's Pnin, I came across this passage describing the eponymous Professor's search for rooms to rent in a private house. These houses, while differing in many respects, 'had one generic characteristic in common: in their parlour or stair-landing bookcases Hendrik Willem van Loon and Dr Cronin were inevitably present .... exchanging looks of tender recognition, like two old friends at a crowded party.'
 Hendrik Willem van Loon was a name I knew, if only as the author of such ambitiously titled volumes as The Story of Mankind and Man the Miracle Maker – but who was his bookshelf buddy 'Dr Cronin'? The name of A.J. Cronin came to mind, but surely this Scottish writer of middle-brow fiction wasn't that popular in America, was he? Well, yes, as I now discover, he was. Several of his novels were adapted into Hollywood films: The Citadel, The Stars Look Down, Hatter's Castle, The Keys of the Kingdom, The Spanish Gardener, etc. Cronin and his family even went to live in various parts of America during the war years, which no doubt increased his Stateside fame. He was a hard-working (five thousand words a day!) and hugely successful writer, whose books sold in immense numbers and were indeed a fixture on bookshelves on both sides of the Atlantic.
 And now they languish, unsold and unread, on the shelves of charity shops, exchanging looks – or perhaps now something more like resigned shrugs – with the equally unwanted volumes of Hendrik van Loon. You can always rely on the bookshelves of the representative middle-brow readers of any time – including (oh very much including) ours – to furnish the charity shop and jumble sale stock of future decades.