Warning: this review contains spoilers.
If a Thomas Hardy novel can be characterised by descriptions of landscape and the depiction of its characters within that landscape, then 'The Trumpet-Major' is not a typical Hardy novel.
Hardy adopts a light narrative style with the emphasis on the story of the heroine Anne Garland and her interactions with three suitors, the Loveday brothers (including the eponymous trumpet-major) and Festus Derriman. I found that this story got rather tedious - there were occasions when I felt like telling Anne Garland to "get on with it and make up your mind". The lack of other storylines would have brought some relief from all her dithering, but, unfortunately, there are none.
There is a nice sting in the tail at the end of the novel where Hardy confounds the reader's expectations by not providing a conventional happy ending. Anne Garland's (final) choice of suitor is determined more by sexual attraction than mutual compatibility (though Hardy, of course, cannot explicitly state this).
The novel is populated with 'stock' characters: there is the miller, the soldier, the sailor, the bounder, the actress. Indeed, play-acting is an important theme; characters dissemble, disguise their true feelings, put on an act.
The Napoleonic wars and the threat of invasion are the background against which the story plays out, though, in keeping with the overall tenor of the novel, it is not a serious threat. The episode where the local men drill could come straight from an episode of the television series `Dad's Army'.
'The Trumpet-Major' is a minor Hardy novel, but minor Hardy is better than many other writers' major novels.