I'm afraid I'm 
not currently reading any book. 
But in my humble opinion, it is 
listening that is 
much more important than reading, in order to improve one's proficiency in 
any language.
So if you (or anyone else) 
honestly think my English is 
really good, it's probably because since I was 
born, my parents spoke to me in English (or at least some form of Singlish) 
nearly all the time (which is also why my Chinese/Mandarin is 
much worse than my English); and during my 
teenage years (in the 
second half of the 19
90s), because I 
used to be a 
fan (
) of:
en.wikipedia.org/wiki/Manchester_United_F.C.
I used to 
listen nearly everyday to the:
singaporeradio.net/radio-station/bbc-world-service-singapore-889-fm.html
initially focusing on "Sports Roundup":
bbc.co.uk/worldservice/programmes/sports_round.shtml
but as I grew older, I became more interested in other BBC radio programmes and, eventually, 
British films (mostly from the 20th century), such as:
en.wikipedia.org/wiki/Howards_End_(film)
en.wikipedia.org/wiki/The_Remains_of_the_Day_(film)
starring one of my favourite 
British actors:
en.wikipedia.org/wiki/Anthony_Hopkins
Also, my favourite British TV drama is the six-episode adaptation of:
en.wikipedia.org/wiki/Pride_and_Prejudice_(1995_TV_series)
which I used to watch at least two or three times during the 1990s after my father bought the video tape.
But since my mid-20s (over ten years ago), I've 
not been reading as many English books and watching as many English movies/TV shows as I used to 
before my mid-20s, simply because I have 
finally concluded that 
Japanese culture is the 
best (even though it's obviously still 
far from perfect) in the world!