Before I get into the nuances, I should give the bird's-eye view: this is a good collection, and a valuable introduction to contemporary mainstream poetry. It puts a wide array of techniques on display, and it gives a clear sense of how far "experimentation" has taken the state of the art. The biographical secondary material, bolstered by a keen interpretive eye, helps frame this collection and provides an intelligible angle for thinking about through the material. That's my high-level overview, and like any view from a distance, it tends to obscure the cracks that closer inspection brings out.
The first issue is that the book's thesis statement is all mixed up. Hinton seems to be tracking a couple of motifs -- the influence of Chinese poetry, the development of the ecopoetic tradition -- but instead of making a real study of these themes, he dilutes them into a broad argument about the state of avant garde poetry and the nature of language itself. Thoreau, the moment of "contact," imagistic versus collage... he touches on so many topics, it starts to seem undercooked.
Unfortunately, this is further exacerbated by the concluding section, where Hinton takes a clumsy stab at unifying all these motifs into a big thesis statement. His argument is something about language being mimetic in nature since the advent of writing, and about pictographic writing and avant-garde poetry subverting this tendency. It's not supported by any reading or citation, and it doesn't have the rigor to feel philosophical. There has been a LOT of analysis and debate about the nature of language, and Hinton seems blithely unaware that he's engaging with these longstanding discussions. A more modest, more reflective, and perhaps more personal tone is called for, I think.
The other problem is bigger in nature. As he struggles to make these explicit arguments about the nature of language and contemporary poetry, Hinton is making another argument implicitly: the argument that these poets, his chosen innovators, represent the true backbone of contemporary poetry, some kind of canon that we should privilege over other writers and traditions. I honestly don't like imputing that kind of claim to an author when it's not made explicitly... but how else are we to read statements like "These poetic strategies and the philosophical ideas embedded in them represent the fabric from which the entire range of modern poetry is made" (p 311, after summarizing the primary intellectual threads in the book).
And this is hard to defend. Without a doubt, a picture emerges of poetry being built on a white academic male backbone. It erases all the poetic traditions that make this such a rich medium... for Hinton, Langston Hughes isn't part of the "fabric," nor Maya Angelou, nor any of the confessional or language poets, nor the spoken word tradition. This is a book written in 2017.
So for a survey of poetic technique and innovation in the avant garde, by all means, make this book part of your education. But remember the importance of a wide-ranging appetite and a critical eye... and keep this one clearly in context.