Tessa Quayle is a fictional character from the novel "The Constant Gardener," written by John le Carré. She is portrayed as a passionate and idealistic woman who is deeply concerned about social justice and human rights, particularly in Africa. Her dedication to these causes drives much of the story's conflict. In the narrative, Tessa's mysterious death prompts her husband, Justin Quayle, to investigate the circumstances surrounding it. As he delves deeper, he uncovers a web of corruption involving pharmaceutical companies and unethical practices in drug testing, highlighting the themes of exploitation and moral responsibility.