I'm currently reading a historical novel, based on the diaries
of a english seafarer. It's called Samura William: The Englishman
who opened Japan written by Giles Milton, and my short 20-page
stint of reading has got me hooked.
The one I bought is apparently the 'sale' paperback version of
it. A few different covers as well. This is the one I have, which I
think is visually appealing comparing it to the rest.
Part of the review. 
Samurai William is an extremely readable,
scholarly study of the opening (and in 1637, the closing) of Japan
to western trade. Using many primary sources, Milton creates an
exciting story of how Japan came to be "discovered," what its
values and culture were, and why the intrusion of the west and the
possibility of trade were eventually rebuffed. The contrasts Milton
sets up throughout the bigoraphy attest to his appreciation of 17th
century Japanese society. Though he clearly does not agree with the
sense of quick justice, the immediate executions, and the brutality
and torture carried out by the Japanese in the name of justice, he
shows his admiration for their courage and sense of honor, their
loyalty and respect for authority, their beautifully constructed
and aesthetically pleasing gardens in Kyoto, the grandeur of the
palace in Edo (now the Imperial Palace in Tokyo), along with more
mundane characteristics, such as their concern for hygiene and
bathing, their medical practices (including acupuncture), their
care for their appearance and cleanliness, their careful food
preparation with its emphasis on freshness and healthiness, and
their quiet self-control. The obvious contrasts to the mores of
western society show how the hierarchical, non-individualized focus
of the Japanese led to a more community-oriented society with a
much higher level of "civilization" than that of the
adventurer-traders, who were out for personal benefits, no matter
the costs to their host country. So power-hungry were the
westerners at the trading posts and the Jesuits in their parishes,
that it is easy to see why Ieyasu's grandson eventually banned them
all in order to preserve his own society.
Though Samurai William Adams is the real-life role model for
James Clavell's Shogun, I found him far more true
to life and interesting in this book. Neither romanticized nor
idealized, he exists here as a man with flaws, often speaking in
his own voice. His life as a seaman and his life in Japan, are
fascinatingly portrayed, attesting both to Milton's scholarship and
his imagination as he recreates successfully the two cultural and
social milieus in which Adams spent his two very different
lives.
- From http://www.mostlyfiction.com/adventure/milton.htm
More at
http://www.amazon.com/Samurai-William-Englishman-Opened-Japan/dp/B000BTH562/ref=ed_oe_p_bargain
