Lincoln in the Bardo is not an easy read, at least not initially, and the author George Saunders admits as much in an interview with Zadie Smith.
Whole swathes of the book are made up of verbatim quotes from various historical sources, which I cut up and rearranged to form part of the narrative (…) The beginning is strange, and I did a lot of work calibrating that so that a reader with a certain level of patience would get through it and, in the nick of time, start to figure out what was going on. 
A friend, to whom I recommended Lincoln, abandoned the effort to read it fairly early in the text remarking: “I wish someone could tell me how to read it.” This review is, in part, an effort to do that, as well as a celebration of my delight in this marvellous piece of writing.
While Saunders’ technique of subjecting the reader to myriad different voices makes for a challenging read it has an important contribution to make to both the liminal and subliminal effects of the work. It works on the level of the narrative but at a more subtle level it shifts the perspective to one where the concept of identity is far less solid than we are accustomed to imagine.
The prime quality of literary prose—that is, the thing it does better than any other form (movies, songs, sculpture, tweets, television, you name it) — is voice. A great writer mimicking, on the page, the dynamic energy of human thought is about as close as we can get to modelling pure empathy.
Lincoln can usefully be viewed as an experiment in the use of voice and its ability to create the appearance of identity. A clue to this is in the very first lines of the book where Saunders’ creates confusion as to the identity of the speaker by opening a novel with the name Lincoln in the title with the voice of an anonymous stranger. A stranger who, at first, just might be Lincoln. And then something the voice says creates a cognitive dissonance with what we think we already “know” about Lincoln.
Reading on we hear what numerous different voices have to say about Lincoln, some of it congruent and fitting in easily with the identity we are building up in our minds for him; some of it contradictory, incongruous, food for a growing insight into how we go about constructing the appearance of identity.
The structure of the novel is indeed strange; but mimicking as it does the process of identity creation and dissolution as posited by Tibetan Buddhism and subjecting the reader to immersion in a world where that process is undisguised by the conventions of everyday life is a stroke of genius.
The word Bardo of the title is a Tibetan word meaning “a transition stage” — I have seen it interpreted as being synonymous with the Christian word Purgatory. However there are some important differences and Saunders has made it clear that he chose the word Bardo deliberately for those differences.
The term Bardo is based on a non-dualistic view of reality in which all phenomenon are simply modifications of the “ground luminosity” of consciousness, which is all there is. So, unlike Purgatory the Bardo is not a place but more a state of mind. It can even happen during embodied life as well as after death. It can continue indefinitely ─ but dissolves in a flash when the mental loops, attachments, and obsessions that maintain its existence, are seen through or released.
A characteristic of the after-death Bardo is that the fixed perceptions of our shared reality no longer provide limits to the mind, which can thus spin out of control so that any unfinished business, attachment, or obsession becomes monstrous. Saunders portrays this in the book by giving his ghosts various physical “deformities”. Like one, poor old Hans Vollman, with his permanent erection.
Another condition prevailing in the Bardo is that every centre of consciousness is transparent to every other. In Christian terms, souls are “naked before God.” So we hear the voices of the ghosts unfiltered by shame. What makes this so uncomfortable, and so absolutely riveting at the same time, is Saunders’ absolute mastery of the use of voice. We become one, through his “modelling of empathy” with some strange and unfamiliar obsessions, and some undoubtedly familiar ones.
It is a mark of Saunders skill as a writer that when some of the ghosts, those individual knots of mental obsession, do unravel and dissolve, it seems so natural. Like when we experience the “Aha!” moments of letting go of stuckness in our lives. For some of the ghosts, release comes through a genuine concern and compassion for Lincoln and Willies predicament. For others it comes through an almost accidental failure to obsess, like when we stop a child’s tantrum through distracting them with a bright object.
Lincoln in the Bardo is an exhilarating journey. If you let it do its work it will demolish you. And you will love every wonderful minute of it.
Interview with Zadie Smith. https://www.interviewmagazine.com/culture/george-saunders
 Grace Paley, the Saint of Seeing. George Sanders. The New Yorker. Mar 3, 2017
 Cutting Through Spiritual Materialism. Chogyam Trungpa. 1973 Shambala Publications, Boulder, Colorado