Acknowledgements. Part One: Bekker and his Ideas. 1. Balthasar Bekker and the Spirit Debate. 2. Bekker, the Sabbath, and Dutch Reformed Confessionalism. 3. Cartesianism and the Spirit Controversy. 4. The Friesian Hercules. Part Two: Reaction to Bekker's Ideas. 5. Bekker's Opponents: Confessionalism Under Siege and Cartesianism in Crisis. 6. Cats Not to be Touched Without Gloves: Eric Walten and other Supporters of Bekker. Conclusion: The Deep Structure of the Spirit Debate. 7. Most Attacked and Least Defeated: Confessionalism, Anti Confessionalism, and Religious Controversy in the Dutch Republic. Epilogue. The Death of an Atheist.