According to Hawking, who died in March, the universe is the ultimate free lunch and if the universe adds up to nothing, then you don't need a God to create it. Because the universe was once the size of a subatomic particle itself, it's plausible that it behaved similarly during the Big Bang, Hawking wrote.
He dropped some big bombshells about extraterrestrial life, artificial intelligence, time travel, and his stance on God. "I prefer to think that everything can be explained another way, by the laws of nature".
In his book "Brief Answers To The Big Questions", Hawking wrote that it was "almost inevitable that either a nuclear confrontation or environmental catastrophe will cripple the Earth at some point in the next 1,000 years".
The most famous physicist from Cambridge University, has suffered from amyotrophic lateral sclerosis (als), a disease that left him in a wheelchair and not allowed to communicate without the aid of a machine the greater part of his life.
Hawking said he preferred to think that "everything can be explained another way, by the laws of nature".
In "Brief Answers to the Big Questions", the late cosmologist tackles issues as thorny as the existence of God, the origin of life, the fate of humanity on Earth, and other big questions, with each answer making up a chapter.
And he leaves open the possibility of other phenomena.
Hawking's daughter, Lucy, told CNN that this book is more important than ever because her father's message about the future needs to be heard.
I have been to the furthest reaches of our galaxy, traveled into a black hole and gone back to the beginning of time.
Hawking also ruminated over time travel, writing: "Travel back in time can't be ruled out according to our present understanding, [.] within the next hundred years we will be able to travel to anywhere in the Solar System".
Hawking saw the world on the brink of a "vast transformative change" when he died, she noted, adding: "He's asking us not to go into the future blindly".
And he raised a very good question: "How good is the track record of the human race in using advances in technology for the good of ordinary people?"
Hawking had been a critic of the United Kingdom's decision to leave the European Union, and called Donald Trump a "demagogue" in 2016. After the scientist's death his book was not finished and had to be terminated by colleagues and family members who were connected with his personal Affairs.
If you'd like a copy of Hawking's final book, it's now available on Amazon.
"Remember to look up at the stars and not down at your feet", he wrote.