On my second reading and definitely worth reading more than once—or over and over again as a form of contemplation. This book provides very direct and accessible pointing to non-dual truth.
I feel that Spira ought to give credit somewhere in the text, perhaps in a Preface or Introduction, to the tradition of Advaita Vedanta, and the other non-dual traditions (such as Kashmir Shaivism, Sufism and Ouspensky) that have informed his work. Nevertheless, the way he expresses his understanding and leads others into it, gleaned from these various traditions, in plain, simple English, without any Sanskrit, Arabic, or other intimidating language or association with anything religious (or what people assume is religious according to a narrow understanding of that term), and relying only on what can be verified by direct personal observation, is a very effective method. This is why I feel very inclined to suggest his work as an introduction or preliminary reading before getting into traditional Advaita Vedanta. It definitely helped me make the right connections and to see how what had seemed difficult, abstruse and somehow beyond my grasp is really very familiar and already known—closer than our own breath!—but only veiled by long-practised ignorance in the form of all sorts of unexamined assumptions about the nature of experience and reality. Simply looking closely in an unbiased way at our actual experience, as he exhorts us to do, dissolves those conditioned assumptions, ushering in a fresh and vastly more satisfying view.
Of course, this is exactly what traditional Advaita Vedanta also does, but I think there are many people who would be willing to read Rupert Spira who would baulk at something they see as arcane Indian philosophy, and associated with Hinduism. These people are infinitely better off reading Spira than reading dumbed-down and ineffectual neo-pseudo-Advaita. This is leaving aside that the Direct Path, which Spira teaches (as was taught by Atmananda Krishna Menon, Jean Klein and his own teacher, Francis Lucille), while based in AV, differs from it in its intention to be more direct (as the name suggests!). That is, to take pure awareness as the starting point. (To explain this difference properly goes beyond a Goodreads review). I think it's clear that there are positives and negatives in this approach as compared to traditional AV, and the positives apply only for those who are already highly receptive, intellectually sharp and able to grasp subtlety (which has nothing necessarily to do with academic ability or disposition), and highly motivated to "cut to the chase" without anything in the way of step-by-step pedagogical supports. In other words, those who are already highly qualified.
So as much Spira's work, and that of other Direct Path teachers, could be said to be for the many for the reasons already noted, it's paradoxically only for the few, as has always been the case with all forms of non-dual teaching. (This is not principally due to elitism, although elitism has sometimes been a factor, but to the majority self-excluding due to lack of interest. This remains the case today when the material is widely and often freely available). So it comes as no surprise that the usual prerequisites as stipulated by Advaita Vedanta are dispensed with. I suppose it's assumed that only those who are sufficiently, i.e. minimally, qualified will have the interest and the motivation to pursue the teaching. But it's also explicitly stated that the Direct Path aims to first awaken the awareness of being pure awareness and that after that comes the long, or rather, endless, process of assimilating this understanding into daily life. This is another way of saying that the qualities that are traditionally seen by AV as prerequisites are gradually incorporated into the personality as a result of sustained contemplation, in light of understanding oneself as pure awareness, according to the DP.
I think it would be a great shame for anyone interested in non-duality to omit pursuing the glorious, millennia-old tradition that undergirds Spira's teaching (referring to AV here, which seems to be dominant, while acknowledging his other influences), as this can only add richness, depth and clarity. I believe that while Spira's work is of very high quality as a "pointing-out" method, he has done a disservice to his readers, and to the traditions themselves, in not being more upfront about the influences that shaped his own understanding and making these available to others. I suppose he thinks he has good reasons for that, and it's obviously a considered decision, perhaps not wanting to alienate the tentative, skeptical or "religion"-averse, secular-minded reader, but I feel it's a serious omission. It creates an impression, correct or incorrect, that he wants to appropriate all credit for himself, while standing on the shoulders of spiritual giants.
To this I must add the criticism that he charges money for his teaching, above and beyond what is necessary for hire of venues etc. which violates the traditional approach of making the teaching freely available, with any material contributions being of a strictly voluntary nature. Of course it's necessary to charge money for books and he does make segments of his talks from retreats freely available on You Tube. But why only segments, with full video talks requiring payment? Online group video mentoring seems overpriced given the number of attendees. Perhaps here one needs to acknowledge the fact that Western culture doesn't understand the need to provide support for those who dedicate themselves to spiritual teaching, as is the case in India, such that some feel that set fees need to be charged. I can't agree with this at all, since set fees totally ignore the fact of extreme socio-economic inequality which means that the same fee represents loose change for some and is totally prohibitive for others. It's similar to regressive taxation and it's simply not acceptable in the current climate in particular to be indifferent to such realities, only adding to social injustice. If a teacher really needs to support themselves via some kind of fee it ought to be on a voluntary basis only according to what each person can afford, if anything. No one should be excluded due to inability to pay. If this isn't enough, then the teacher can get a regular day job and teach part-time. I can't know what is in the heart of Spira or anyone else, so I'm not levelling this as a condemnation of his character. I just feel compelled to state my own view on these matters. While it's inescapable that we inhabit a ruthless capitalist order, the intersection of capitalist "values" with spirituality can never be a healthy one, given that capitalism involves a repudiation of anything that can be considered genuine spirituality.
However, I don't want these misgivings to prevent anyone from reading Spira's work. The bottom line is that I think anyone who wants to understand themselves and the nature of reality will benefit enormously. Spira's work is a great way to get started on the path and may well take some all the way. In the end, it's not what we've read or heard but what we directly realise that matters when it comes to non-duality. Once that realisation occurs, any further reading is simply for deepening pleasure and appreciation.