"Deep Space Probes" is a technical book that focuses on the exploration of the outer solar system and beyond. In its second edition, it addresses the latest research findings that illuminate the necessity and possibilities of exploring interstellar space. The book discusses the challenges associated with building highly advanced robotic spacecraft required for these journeys. It explains how intelligent, autonomous spacecraft can be developed to make important decisions without human intervention. Additionally, the potential for human travel to interstellar space is explored, along with the enormous challenges that come with it. A new chapter on holographic message plaques for future interstellar probes, a project funded by NASA, complements the content of this edition.