Do you or don't you?

Do you or don't you write in a book that is.
I've talked about it on here before, but there's been some interesting debate over at Stuck in a Book about the whole matter and I was slightly disconcerted to see a long line of "would never dream of it" commenters, all suffering from Chronic Antipencillitis.
Surely I can't be the only miserable offender?
Feeling mildly of the inferior 'spare though them that confess their faults' mindset I bravely posted a 'come on you lot live dangerously' comment of my own just to make myself feel better and redress the balance.
Perhaps the other book defacers would delurk and join me and the penitent would be restored.
Except I'm not in the least bit penitent.
In fact, I scribble in books and I'm proud of it and to my knowledge no one has died as a result.
Of course I'd never write in a book that belonged to anyone else, but books that are mine whilst I'm on earth seem fair game and I now write in every one I read.
I don't think I'd be able to write this blog if I didn't have my pencil quotes and underlinings to go back to, plus my page at the front.Nothing sacred about my books, they are living and working extensions of my mind which as I get older is feeling slightly more full to overflowing, marginalia becometh a necessity not a sin.
Words that sum up the book as I'm reading, often a family tree if it feels complex, page numbers and gems of lines from the author, sometimes a message that the book will have hit me with suddenly and like a sledge-hammer, often a flash of blinding truth gone in an instant unless I write it down.
Don't anyone suggest a notebook or post-it notes because those are never around when you need them whereas I have furnished the entire house with pencils.
I am heartened in that case to read in The Guardian that Nicholas Lezard has the same disease. My books would look very familiar to Nicholas and be unlikely to induce a bout of apoplexy because here's what he does,

" I have a method when reviewing books that involves making a pencilled note on the flyleaf whenever the author makes an interesting point. Just a page number and a short memory-jogging quote"

Thank goodness for that.
To get a book that has someone else's marginalia is even more special somehow.I have a beautiful first edition of A Writer's Diary by Virginia Woolf, in its original Vanessa Bell dust jacket, complete with that first owner's thoughts scattered throughout.
A list of page references on the endflap and I consider endlessly the connections between them.
What were they researching?
I ponder their lives.
To Hilary from Kenneth, Christmas 1953. I was three months old.
I share their reading of this book and I've added a few thoughts of my own, as if to carry on the unbroken thread of reading and loving this book down the years.My books are lent to me while I'm living and breathing, one day they will move on. It all then makes me feel strangely honoured and privileged and somehow my scribbling becomes essential.
Perhaps whoever gets it next may read mine and add theirs, better not leave this one to Stuck in a Book in that case:-)