"…revenge against a brother whose love for her waned after she caused the collapse of his friendship with Lou Salomé. The book also examines their family dynamics, Nietzsche’s dismissal of his sister’s early writing career, and the effects of limited education on intelligent women. "
His illness and death may not have been caused by syphilis after all. From Wikipedia:
Nietzsche’s mental illness was originally diagnosed as tertiary syphilis, in accordance with a prevailing medical paradigm of the time … The diagnosis of syphilis has since been challenged and a diagnosis of “manic-depressive illness with periodic psychosis followed by vascular dementia” was put forward by Cybulska prior to Schain’s study. Leonard Sax suggested the slow growth of a right-sided retro-orbital meningioma as an explanation of Nietzsche’s dementia; Orth and Trimble postulated frontotemporal dementia while other researchers have proposed a hereditary stroke disorder called CADASIL.