If Friedrich Nietzsche kept his “gaze … fixed beyond all that is ephemeral,” seeing himself as “untimely,” Sue Prideaux’s I Am Dynamite! (Tim Duggan, $30) shows how very timely the “philosopher of perhaps” remains. Prideaux looks closely at the thinker’s family, friendships, health, and travels, tracing the development of his ideas within larger personal and cultural contexts. So rich are these contexts that at times they threaten to overwhelm the ideas. Prideaux gives generous selections from Nietzsche’s letters as well as the letters and journals of his sister Elisabeth, Cosima Wagner, Paul Rée, Jacob Burckhardt, and others; combined with her often witty and always sharp comments, these actual voices bring even the secondary characters to life. The narrative is also full of telling and indelible details, like the “Renaissance painter outfit” Richard Wagner wore for his first meeting with Nietzsche. Prideaux’s accounts of Nietzsche’s life-long ill health, when he was incapacitated for weeks with headaches, nausea, and sensitivity to light, reveal him as a courageous and vulnerable man as well as a formidable thinker. But when he was incapacitated mentally and physically for the last years of his life, he was at the mercy of his sister Elisabeth, who recreated her brother in the image of proto-Nazi. Prideaux untangles her distortions from Nietzsche’s rejection of systems, restoring his “blazing if baffling vision that challenges us to think for ourselves.”