There are a lot of interesting letters quoted here. To me, the best ones are those that are not intended for a wider audience. All letters carry an introduction by the editor, e.g. this one:

Letter No. 006 BILL HICKS ON FREEDOM OF SPEECH BILL HICKS to A PRIEST June 8th, 1993 As an outspoken stand-up comedian with strong, unbending views on the most divisive of subjects, the late Bill Hicks was no stranger to controversy during his all-too-brief career. In May 1993, less than a year before he succumbed to pancreatic cancer at the age of 32, a live recording of Hicks’s Revelations show was broadcast on television in the UK. Shortly afterwards, deeply offended by its “blasphemous” content, a priest wrote to the broadcaster, Channel 4, and complained about the recent screening. After reading the complaint, Hicks, never one to avoid a discussion, replied to the priest directly by letter.

8 June 1993
Dear Sir, After reading your letter expressing your concerns regarding my special ‘Revelations’, I felt duty-bound to respond to you myself in hopes of clarifying my position on the points you brought up, and perhaps enlighten you as to who I really am. Where I come from — America — there exists this wacky concept called ‘freedom of speech’, which many people feel is one of the paramount achievements in mankind’s mental development. I myself am a strong supporter of the ‘Right of freedom of speech’, as I’m sure most people would be if they truly understood the concept. ‘Freedom of speech’ means you support the right of people to say exactly those ideas which you do not agree with. (Otherwise, you don’t believe in ‘freedom of speech’, but rather only those ideas which you believe to be acceptably stated.)

Seeing as how there are so many different beliefs in the world, and as it would be virtually impossible for all of us to agree on any one belief, you may begin to realize just how important an idea like ‘freedom of speech’ really is. The idea basically states ‘while I don’t agree or care for what you are saying, I do support your right to say it, for herein lies true freedom’. You say you found my material ‘offensive’ and ‘blasphemous’. I find it interesting that you feel your beliefs are denigrated or threatened when I’d be willing to bet you’ve never received a single letter complaining about your beliefs, or asking why they are allowed to be. (If you have received such a letter, it definitely did not come from me.)

Furthermore, I imagine a quick perusal of an average week of television programming would reveal many more shows of a religious nature, than one of my shows — which are called ‘specials’ by virtue of the fact that they are very rarely on. All I’m doing in ‘Revelations’ is giving my point of view in my language based on my experiences — much the same way religious broadcasters might organize their programs. While I’ve found many of the religious shows I’ve viewed over the years not to be to my liking, or in line with my own beliefs, I’ve never considered it my place to exert any greater type of censorship than changing the channel, or better yet — turning off the TV completely.

Now, for the part of your letter I found most disturbing. In support of your position of outrage, you posit the hypothetical scenario regarding the possibly ‘angry’ reaction of Muslims to material they might find similarly offensive. Here is my question to you: Are you tacitly condoning the violent terrorism of a handful of thugs to whom the idea of ‘freedom of speech’ and tolerance is perhaps as foreign as Christ’s message itself? If you are somehow implying that their intolerance to contrary beliefs is justifiable, admirable, or perhaps even preferable to one of acceptance and forgiveness, then I wonder what your true beliefs really are. If you had watched my entire show, you would have noticed in my summation of my beliefs the fervent plea to the governments of the world to spend less money on the machinery of war, and more on feeding, clothing, and educating the poor and needy of the world … A not-so-unchristian sentiment at that!

Ultimately, the message in my material is a call for understanding rather than ignorance, peace rather than war, forgiveness rather than condemnation, and love rather than fear. While this message may have understandably been lost on your ears (due to my presentation), I assure you the thousands of people I played to in my tours of the United Kingdom got it. I hope I helped answer some of your questions. Also, I hope you consider this an invitation to keep open the lines of communication. Please feel free to contact me personally with comments, thoughts, or questions, if you so choose. If not, I invite you to enjoy my two upcoming specials entitled ‘Mohammed the TWIT’ and ‘Buddha, you fat PIG’. (JOKE)
Sincerely,
Bill Hicks

And Virginia Woolf's heartbreaking final letter:

Letter No. 010
I CAN’T FIGHT ANY LONGER
VIRGINIA WOOLF to LEONARD WOOLF
March, 1941 By the age of just 22, influential novelist Virginia Woolf had already suffered two nervous breakdowns – brought on, it’s believed, by the deaths of her mother and half-sister in quick succession, and then her father some years later. Unfortunately, the struggle didn’t end there for Virginia and she fought off numerous bouts of depression throughout her lifetime, until the very end. One evening in March 1941, Virginia attempted to end her life by jumping into a river; however, she failed and simply returned home, sodden. Sadly, she persisted, and a few days later, on March 28th 1941, she tried again and this time succeeded in escaping a lifetime of mental illness. On the day of her death, unaware of her whereabouts, Virginia’s husband, Leonard, discovered this heartbreaking letter on their mantelpiece. Her body was found weeks later in the River Ouse, the pockets of her coat filled with heavy rocks.

Tuesday.
Dearest, I feel certain that I am going mad again. I feel we can’t go through another of those terrible times. And I shan’t recover this time. I begin to hear voices, and I can’t concentrate. So I am doing what seems the best thing to do. You have given me the greatest possible happiness. You have been in every way all that anyone could be. I don’t think two people could have been happier till this terrible disease came. I can’t fight any longer. I know that I am spoiling your life, that without me you could work. And you will I know. You see I can’t even write this properly. I can’t read. What I want to say is I owe all the happiness of my life to you. You have been entirely patient with me and incredibly good. I want to say that – everybody knows it. If anybody could have saved me it would have been you. Everything has gone from me but the certainty of your goodness. I can’t go on spoiling your life any longer. I don’t think two people could have been happier than we have been.
V.

There are some letters which are a bit drab, very American in nature—i.e. that display how the editor is an American, by which I mean that he's inward-looking, more than taking in many letters from many cultures—but overall, an interesting book.