This book was written by Mercedes Lackey and she was among a growing group of authors who worked to produce literary works that had developed female characters that stand away from normal gender stereotypes.
"By the Sword" is reported to be her favorite book that she produced and through the years I have re-read it many times. It is full of adventure, heroism, and thrill. This book is a coming of age book that covers the development of the female protagonist as she starts to challenge the place that society tries to bind her to.
At the start of the book, Kero is introduced as a single daughter in charge of running her father's keep since her mother passed away. Thus the role of organizing her brothers wedding is thrust upon her and she is left in charge of organizing the large event. During this, the keep is attacked and the bride is kidnapped with the groom (Kero's brother) and the majority of the men left wounded at the keep.
Thus, Kero takes off her skirts and goes to her grandmother's keep for aid. Once there she receives a magic sword and thus her story starts. Some might expect the brother to go rushing off to save his bride, but not this tale. It is Kero who takes up the path and goes to rescue her soon to be sister in law and by doing so throws awry societal expectations.
From this start, the life challenges that Kero undergoes shift dramatically and are readily realistic in terms of emotional development and relationships.
I would recommend this book to any one who likes to read a book that has a strong female protagonist that relies not just on her brawn but also on her brains.