I just read this book myself, this summer and really enjoyed it. It was wonderfully witty and chatty and I read through it in two sittings, I think, because I couldn't put it down. Even the parts relating things that were really terrible, such as a concentration camp, were told in a gentle, whimsical way. I read somewhere that the author chose an epistolary style because she thought it would be easier!
However, I felt that towards the end, the book fell apart somewhat. That is, some of the scenes were ludicrous and made the characters seem not just quirky (as they had all along) but downright ridiculous. I wish some of those parts had been written in a different way, and some left out entirely. But I haven't run across anyone else who felt that way, so I'm obviously in a minority.
But the rest of the book was so wonderful that I highly recommend it.
Someone asked about other books written in an epistolary style. I've only read one other, and really enjoyed it, as well. I read it many years ago -- probably in the '80s -- so I can't recall the title or the author's name. I believe she was a fairly popular author at that time. The book was composed of all the correspondence of a woman starting when she was a young child and going all the way through to nearly the end of her life. I believe it began in the late 1800s and went through to the 1950s or perhaps 1960s.
Does anyone recall the title? I remember that I did enjoy the book, and I would recommend it for someone who likes the epistolary format.
ETA -- I found the book (let's hear it for Amazon).
It was A Woman of Independent Means
by Elizabeth Forsythe Hailey. Talking about it has made me want to read it again, think I'll try to get my hands on a copy......