Here are some key points about Pais:
* He is known for his unconventional and often highly speculative ideas on aerospace technology. Some of his concepts include:
* High-frequency gravitational wave propulsion: Using gravitational waves to move spacecraft faster than the speed of light.
* Hypersonic, antigravity propulsion: Using an advanced electromagnetic field to achieve hypersonic speeds and potentially antigravity effects.
* His work has been controversial and subject to scrutiny from both scientific and military communities.
* His papers and patents have been cited by some as evidence of secret government programs exploring advanced technologies, though this is largely speculative.
Overall, while Pais has not written any books, his work has garnered significant attention and debate within the scientific and aerospace communities, despite the lack of strong evidence to support his claims.