Two series Lackey published early in her career was Vows and Honor, dealing with Tarma and Kethry and the Valdemar series, dealing with Heralds, a police/military force bonded with magical horses. Both series were favorites of mine when I was a decade younger and still hold up now. Although I think By the Sword could stand alone, I'd read those novels first. The Vows and Honors books are first chronologically speaking and start with The Oathbound. The first Herald Trilogy, begin with Arrows of the Queen and end with Arrows Fall. Arrows Fall overlaps a bit with By the Sword and so would act as a spoiler. Having loved the other books set in this world, the small roles in this book by the earlier characters such as Tarma, Kethry and Talia was a treat. I found the protagonist, Kerowyn, appealing. I like how this novel dealt with life in a mercenary company and in that way is reminiscent of Moon's The Deed of Paksenarrion or the Tarma and Kethry novel, Oathbreakers. By the Sword was an engaging and fun read.