As the reviewer below remarks, 'Rogue Officer's predecessor, 'Brothers of the Blade', was not the best book in the Fancy Jack Crossman canon. 'Rogue Officer', however, harkens back to the glory of the Crimean books, matching my personal favourites, 'Devil's Own' and 'Valley of Death'. There is a good mix of subterfuge and military action, and readers of the Crimean books will revel in the return of an old face.
If you're thinking of trying a Crossman book for the first time, this would be a good place to start as any. Then go back and read the Crimean books...