In Robert Calasso's The Art of the Publisher, the author distills to art of publishing to form - the "capacity to give form to a plurality of books as though they were the chapters of a single book".
This is a fascinating concept, particularly applicable in a world where branding is both understood as an art... and almost entirely ignored in the publishing industry. The most overt demonstration of form is, of course, the art and design of covers - and Calasso dedicates many thoughtful pages to the role of cover(s) across a publisher's list.
But he also points out, quite thoroughly, that the first and foremost platform for form is judgement: the publisher's choice of when to 'say no' (in commissioning and otherwise). Form applies both the content of books and their presentation.
Form is found in the details as well, and everyone in the brand world will appreciate it when Calasso encourages the reader to:
...[t]ry to imagine a publishing house as a single text formed not just by the totality of books that have been published there, but also by all its other constituent elements, such as the front covers, cover flaps, publicity...
I find it much easier to find evidence of Calasso's form in small presses. Visually: in terms of a consistent cover aesthetic. And in taste: a small press generally has a single taste-maker involved, and, intentional or not, all the books will fit their 'judgement'. When the same person is commissioning the books, planning the events, writing the tweets and laying out the cover... crafting form is almost unavoidable.
In larger publishing houses, of course, there are specific editors - and even specific imprints - all with their own visions and taste. But the larger the publisher, the more this is invisible to the consumer.
There's also something to be said about how conflicting brands will detract from form as well. Larger houses can afford to buy larger authors, the sorts of authors that draw readers on name recognition. Smaller publishers have to build their publisher brands more, and be more recognisable as a publisher. Lee Child readers don't care who publishes Lee Child. Whereas, say, a Jurassic London reader was buying a 'Jurassic London' book. That's both exciting and, of course, totally limiting. The Lowest Heaven was a 'Jurassic London' book. The number one reason someone bought a Jurassic London book was because they bought another Jurassic London book. Jack Reacher in Night School is not a Bantam book. Whether one buys the latest Reacher will make no difference as to buying another Bantam book (at least, one not by Lee Child).
[I'm using Jurassic as an example solely because it is the closest small press to hand, not because I think we did an exception - or even intentional - job of creating form. In hindsight, well,... I wish I had read Calasso's book six years ago, dernit.]
Beyond size, most of the examples I can think of are dated. I think my beloved Fawcett Gold Medals have form. And probably their contemporary equivalent in Hard Case Crime. I think there's something interesting about Lin Carter's work with Ballantine Adult Fantasy - although that's essentially a one-man-band again. Vertigo had form. Marvel and DC do not. I'd entertain arguments for Tor.com, but I suspect, in regards to Calasso's quote above, there's probably more that's characteristically 'Tor.com' in the non-book aspects of the publisher, rather than in the books themselves. Baen, possibly? Black Library, although that strays into tie-in fiction, and is a different kettle of fish.
Obviously my heart is in genre publishing, and you'd think genre would be easier, given all the books already have one layer of thematic filter applied. But perhaps that makes it more difficult to create a form: parsing why one SF list is distinct from another SF list may be more challenging to express, rather than less.
Which publishers - past or present - have form?