Let's get one thing straight first.
I hate, hate, hate this version of the cover. It's hacky, it's tacky, and it sends the wrong impression of the novel. I also hate that the critic excerpt the publisher decided to go with referred to this book and Trevanian's writing as an "airport paperback". Plus, there is really never a point in the story where anyone is wielding a katana. So, shitty cover job.
This book is not just some "airport paperback". Trevanian is no "airport novelist". The biggest crime this book commits is supporting a white savior figure, but even then I'm hesitant to say that's what it is outright.
What this book is is an insightful look into the mind of a man who was born into a world where he was already outside the zeitgeist, a stranger in a strange land. Nicholai Hel Alexandrovich was born to a aristocratic coupling of a Russian noble and German military man in China, shortly before the outbreak of WWII.
When China falls to the Japanese, Nicholai is but a boy, and when his mother passes, a Japanese General who has been residing in their family home takes charge of Nicholai's upbringing. He introduces him to the Japanese game Go and the concept of Shibumi, which is best described (albeit poorly) as a kind of understated, unobtrusive beauty.
Nicholai is sent to Japan where he is educated under the teachings of a Go master, all while WWII rages on. Nicholai becomes "culturally Japanese" and learns of his ability to withdraw mentally outside of himself, a state the book calls "mystic transport.
After the Japanese surrender, Nicholai oberves how the nation is ravaged by western influence and the fallout of war. Starving and homeless for months, he eventually lands a job as an interpreter for the Occupying Army and a decoder for American intelligence operations. All the while, he resents these intruding forces and the way they bastardize Japanese culture.
Through the course of the novel, we see that Nicholai makes his way in the world as a world-class assassin, after years spent in solitary confinement and being released as a government asset. He eventually retires to the Basque country, though tumultuous events caused by a group of neo-activists cause him to become embroiled in a conflict that isn't his own.
The novel is an amazing take on the impact of culture and how being involved in a culture that isn't your own can deeply affect the way you view the world. It offers cutting descriptions of American imperialism, racism, and class boundaries. The book is effectively a commentary on society and the power-hungry people in charge.
The main enemy is the Mother Company, who seem to be responsible for all shadow councils all over the world, as well as keeping track of power balances between nations. Nicholai, who seeks only to live a life of Shibumi, becomes wrapped up in a conflict between them and a Jewish commando outfit.
The novel is masterfully written, by the man who wrote a heist novel so well that people copied the heist in real life and got away with it. He wrote a another novel where a mountain is climbed, and in filming it, the mountaineering expert died. This man writes things that are almost too real for real life.
But, as the cover says, it's an "airport paperback". So as amazing as it is, it isn't a particularly challenging read. Though it is amazingly well-thought, insightful and will have you highlighting passages all throughout.
Do yourself a favor and add this one to your list. You'll be happy you did.