The other reviews on of this book on amazon are telling. One reviewer refers to Caplan as "Dr. Caplan." As far as I can tell, she is not a doctor of anything. Another identifies her as a "pyschotherapist," but the author bio in the book identifies her only as a counselor.
In other words, it appears to be easy to presume that someone is an authority on something because they've managed to get a book published about it. But on closer examination, Caplan's authority seems pretty thin to me. She is basically a woman who has been involved in various alternative religion scenes for a few years (mostly Hindu-derived, Lee Lozowick in particular), has conducted some interviews, and has a lot of opinions on the subject that she wants to share. Many that I happen to agree with. Nonetheless, I was forced to conclude that she hasn't earned the stature to sell me a book full of her opinions, and consequently the book isn't very good.
The author's bio in the book states that "she was educated at the University of Michigan, California Institute of Integral Studies, and the Union Institute and Unviersity in Cincinnati," and that "her degrees are in Anthropology, Counseling Psychology and Contemporary Spirituality." So in other words, it appears that she got a bachelor's degree in Anthropology, got certified to be a counselor, and also got an unspecified degree in a nonsense field from a bogus institution.
Perhaps none of this would matter if Caplan was a better writer, but unfortunately her prose is muddled and scattershot. She launches into a defense of the validity of "enlightenment" as a goal and the "guru" as a paradigm without taking the time to define either one. She characterizes alternative models of teacher-student relationship such as the "spiritual friend" and the "mentor/guide" model as Western attempts to water down uncomfortable foreign traditions, as if the guru-disciple relationship was the only normative traditional one, appearing not even to recognize that in some traditions (Theravada Buddhism comes to mind) the former model is the norm and there are no "gurus" per se. I suppose she cannot afford to acknowledge the counterexample, as it invalidates her argument that gurus are necessary.
Speaking of which, Caplan's answer to the rhetorical question of the title is, yes you need a guru if you are serious about the spiritual path, although there are a lot of charlatans and abuse out there. But she tends to extrapolate unreflectively from her own experience in the Vedanta context as if there was some big undifferentiated "Eastern Spirituality + various shaman traditions" about which one can generalize. In fact, she actually says a number of times, "the Eastern teachings say . . ." as if there was any such singular thing.
The author states "the contents of this study come from masters and disciples of numerous traditions, spiritual academicians (sic), scriptures, and over 15 years of my own contact and personal involvement with just about every kind of guru, shmuru, tulku, sensei, sheik, shaman, rabbi, therapist, sage, mentor, "no teacher", healer, psychic, and divine mother you can imagine and not imagine." That about tells you what you need to know. Somehow she managed to land interviews with some notable names, but otherwise the book is as glib, flakey, and unworthy of serious consideration as the passage above suggests. Which is unfortunate, because the topic is an urgent one.