Unlike the practice of many other disciplines, historians publish a lot in collections of essays – normally not all their own essays, but collections ‘from divers hands’ edited by one or two colleagues. These collections often arise from a conference on a focused topic. (Sometimes a conference can also materialise as a special issue of a journal.)
Sometimes they have been put together as a Festschrift for a senior or retiring academic by their students. Sometimes they just flow from the conviction of the editor that there is a topic that a lot of people are working on independently, and which would benefit from being brought together in one package. In many respects chapters in books function just like journal articles. You’ll get asked to submit your paper to the editor, who will decide whether it does indeed fit into the theme of the volume. You may have been supplied in advance with a proposal for the volume, which sets out a minimum common programme, to which your chapter should seek to conform.
Some degree of peer review will be applied. It may be that the editor has had the proposal for the volume peer-reviewed by the publisher (in which only an abstract of your chapter has been included); more rarely, the publisher will want to peer-review the whole volume, once all the manuscripts have been submitted. Once the editor and the publisher have accepted the final text, your chapter will be copy-edited and proofread much as a journal article is. When it’s published, you will probably receive one free copy of the book. But chapters in books have additional pluses – and minuses.
Put plainly, standards are not so high for edited collections, so it’s easier to get into them, especially as an early-career scholar. It can be gratifying to be solicited for publication, rather than having to undergo gruelling anonymous peer-review on a competitive basis for a journal. It seems like an easy way to build a publication record from scratch. But that’s why standards are not so high – the peer-review tends to be light and non-competitive, a pretty basic minimum standard only being applied. Collections of essays tend also not to get wide readerships.
They’re not (at present) much available online, and they will likely sell only 150-350 copies at very high prices to a select group of libraries. Of course, we all know chapters in books that have revolutionized our fields, and collections on specialist topics can be very innovative, even pioneering.
On average, though, they’re not. So by all means be flattered by a solicitation – take the opportunity to publish – but tread carefully, and don’t make a habit of publishing exclusively through these outlets.