Try devouring this Buddhist Parable:
"A man is struck in the chest with a poison arrow. A surgeon rushes to his side to begin the work of saving his life, but the man resists these ministrations. He first wants to know the name of the fletcher who fashioned the arrow’s shaft, the genus of the wood from which it was cut, the disposition of the man who shot it, the name of the horse upon which he rode, and a thousand other things that have no bearing upon his present suffering or his ultimate survival. The man needs to get his priorities straight. His commitment to thinking about the world results from a basic misunderstanding of his predicament. And though we may be only dimly aware of it, we, too, have a problem that will not be solved by acquiring more conceptual knowledge."
The term 'Spirituality' is more colluded with religious doctrines obliviously. And over time, many presume that both are the two sides of a same coin. Astronomers and Astrophysicists, Physicists like Sagan, Neil Tyson, Brian Cox gets some of us 'spiritually' enlightened, getting awe with the depth of understanding than previously believed possible when they start talking lyrically about their specialized fields. Some Writers like Shakespeare, Kurt Vonnegut(personal option) make many people realise that they could lead a happier life, prouder to be alive than previously believed possible. Musical artists like Beethoven, Mozart make the same using the tools and medium they knew. Now, take a religious person listening to a 'Spiritual' Guru, he would feel connected and profound relevantness of his existence with respect to that Guruji's words and view of world. Sam Harris connects the word with understanding the brain and it contents both physical and emergent, of course rational content free of dogma, which is equally important to knowing the worldly facts and phenomena.
The Book deals with signifying the importance of being "spiritual" which the author implies removing the illusion of self. By "illusion of self" he meant that the illusion of inner-self, some kind of agenticity within our body having control over it which adds up concepts of soulful mind duality, and freewill stuffs. And breaking this illusion of the self, he says that our minds can have different and better 'conscious' experiences irrespective of our emotional states. It's not a matter of thinking more clearly about experience; it is the act of experiencing more clearly, including the arising of thoughts themselves and the problem is not thoughts themselves but the state of thinking without being fully aware that we are thinking. Even though he explained things in simpler terms, I felt like I was listening to the most complicated man alive. He explored the split brain phenomena, Nature of Consciousness, Contemporary meditation techniques as per the western as well as the Eastern cultural and psychological understanding, the yogis, gurus who were considered as enlightened (still many consider themselves enlightened) in context to the core objective of enabling the readers to understand about our mind a little better and more profound. He also had his exquisite intellectual ponderings on the effects and usage of 'drugs'. The term 'drugs' collectively defines a wide variety of neurotransmitters and chemical enhancers of neural activities in which substances in both category has both neurotoxic, epileptic as well as excrescence enhancing tool for consciousness. Collectively labelling them as 'drugs' disables us to have intellectual discussion on the ethical, psychological, biological, legal effects amd usage of such substances like Psilobin, DMT, Ketamine, LSD, MDMA (commonly known as Ecstasy), etc.,. It is also worth noting that some substances stereotypically labelled as 'drug' has lesser effects than widely legalised Alcoholics and tobacco.
"The power of psychedelics, however, is that they often reveal, in the span of a few hours, depths of awe and understanding that can otherwise elude us for a lifetime."
He repeated the phenomena many times with various illustrations to make sure the listeners/readers could really understand and ponder out the stuffs. As Carl Sagan once said, Brain is a small place with a very enormous space and capabilities.
He used fluids to define the nature and physical foundation of consciousness, as emergent phenomena.
"Consciousness is the prior condition of every experience; the self or ego is an illusory appearance within it; look closely for what you are calling I, and the feeling of being a separate self will disappear; what remains, as a matter of experience, is a field of consciousness—free, undivided, and intrinsically uncontaminated by its ever-changing contents."
Even though I've already read a book of Sam Harris on Free Will, i got to know more about him than being a skeptical neuroscience spokesperson. His early life encounters with drugs, in search of his spiritual encounters inside USA. While he was in his 2nd year at Stanford, he took off 11 years to spend time in India and Nepal, trying to understand the case of which he described briefly in this book.
"I have long argued that confusion about the unity of religions is an artifact of language. Religion is a term like sports: Some sports are peaceful but spectacularly dangerous (“free solo” rock climbing); some are safer but synonymous with violence (mixed martial arts); and some entail little more risk of injury than standing in the shower (bowling). To speak of sports as a generic activity makes it impossible to discuss what athletes actually do or the physical attributes required to do it. What do all sports have in common apart from breathing? Not much. The term religion is hardly more useful.
The same could be said of spirituality. The esoteric doctrines found within every religious tradition are not all derived from the same insights. Nor are they equally empirical, logical, parsimonious, or wise. They don’t always point to the same underlying reality—and when they do, they don’t do it equally well."
Well for general audience, there's nothing novel about this work; Its just about trying to become happy. The Conventional sources of happiness aren't always reliable depending upon various transient conditions. It is difficult to raise a family happily, to keep yourself and the people you love healthy, to acquire wealth and find creative and fulfilling ways to enjoy it, to form deep relationships, to contribute to society in ways that are emotionally rewarding, to perfect a wide variety of skills—and to keep the machinery of happiness running day after day.
See if you can stop thinking for the next sixty seconds. You can notice your breath, or listen to the birds, but do not let your attention be carried away by thought, any thought, even for an instant. Keep away from mobile or computer, and give it a try.
"If your golf instructor were to insist that you shave your head, sleep no more than four hours each night, renounce sex, and subsist on a diet of raw vegetables, you would find a new golf instructor."
There is no question that novel and intense experiences—whether had in the company of a guru, on the threshold of death, or by recourse to certain drugs—can send one spinning into delusion. But they can also broaden one’s view.
Before trying this book, I've checked the reviews of this work and found too many negative reception about it. Many of them indicated themselves as ardent followers of Sam Harris by his support and critical views on religion and his science popularizing façade but disappointed with Sam Harris for supporting the Meditation via 'buddhist' techniques and this illusionary concept of 'self' and many didn't feel like it's science at all because of confusing usage of consciousness. Sam did answer those things in the book itself,
"Search your mind, or pay attention to the conversations you have with other people, and you will discover that there are no real boundaries between science and any other discipline that attempts to make valid claims about the world on the basis of evidence and logic. When such claims and their methods of verification admit of experiment and/or mathematical description, we tend to say that our concerns are scientific; when they relate to matters more abstract, or to the consistency of our thinking itself, we often say that we are being philosophical; when we merely want to know how people behaved in the past, we dub our interests historical or journalistic; and when a person’s commitment to evidence and logic grows dangerously thin or simply snaps under the burden of fear, wishful thinking, tribalism, or ecstasy, we recognize that he is being religious."
Overall, I feel the book is well worth reading, pondering out our brain stuffs. Though the brief summary of the book is very simple but one has to go through every word vigilantly, to avoid confusion, to avoid misconceptions. So I wouldn't recommend it for all.