I am big on comfort reads. If I'm feeling out of sorts, I turn to books first and foremost (well... not quite, but first out of material things anyway). I read when I'm bored, I read when I'm sad, I read when I desperately need to be distracted.
In those cases (well, not so much bored, but the other two), it's important that it's a book that won't have any triggers, and won't make me even more sad. In those cases, it's good to turn to the tried and tested and much loved ones. But of course I don't have to be sad or blue to pick up a comfort read... sometimes I just feel like re-reading a favourite book!
As for the definition of a comfort read... well, really, I'm just going to quote Giraffe Days there:
What is a comfort read? That's an easy one. It's a book that, no matter your mood, you can snuggle down with. A book that you know, because you've read it before, has the power to absorb you, de-stress you, shine a little light on your soul for however long. It's a book where the characters are like family, a book that has associations and memories for you - good ones. A book that's like your best friend, like a cuddly old jumper that you will never throw out no matter how tattered it becomes.
A comfort read is, quite simply, a book you read to comfort yourself with. You know what happens but that's never a problem. It's the characters and the story that you love, like a favourite movie or comforting song. And, for me, I think it needs a happy ending. I want to be left with that feeling of wholeness that is happiness.
The Blue Castle - Lucy Maud Montgomery
I can't remember when Mum first introduced me to this book, but I can't have been much older than 13-14, and I think I've probably read it about once a year since then. It fits all the hall-marks of a comfort read - humour, cozy descriptions, romance and - of course - a happy ending. Although this one is perhaps a little contrived ;)
But generally, almost everything LMM wrote would fit the bill of a comfort read, especially the first four and the last Anne book (a comfort read may be sad in the middle, as long as it has a happy ending!), Jane of Lantern Hill, and Emily of New Moon.
Little House... - Laura Ingalls Wilder
I know it's not one book, but it might as well be, as I seldom read just one :) Although truth be told, I do tend to skip Little House on the Prairie. It's just not nearly as interesting as the others.
My favourites are Little House in the Big Woods (although I'll often skip Father's stories), Farmer Boy, Little Town on the Prairie and These Happy Golden Years. I realise I just listed almost half of the series, but that just goes to show that it might as well be one book, with me reading favourite chapters ;)
I love all the descriptions of how the Ingalls (and Wilder) family lived, I love all the good food descriptions (even if it does make me terribly hungry!), I know the Ingalls family so very well by now, and love 'visiting' them, and it's just generally a nice series of a simpler time, with people generally being nice to each other. I know the latter is probably fabricated, or written through rose-tinted glasses, but that doesn't take away from my enjoyment of it in the slightest.
I've read at least one book in this series yearly since I was 10.
Wizard's First Rule - Terry Goodkind
I first read this in 1997 by recommendation of Christian (my BIL), and have already read it many, many times. It doesn't fit the usual definition of a comfort book, as it has some very unpleasant scenes, but this is where I have to resort to the definition above - it has the power to absorb me, it de-stresses me, and it holds good memories for me. At a time where my life was closed to be turned upside down it was the only book that could hold my attention long enough to read it (and even so, it doesn't now have bad connotations, because I'd already read it so many times by then). It's by far the best book in the series, and draws me in completely.
It's one of those books I really have to be careful not to start reading during the week, because I won't want to stop neither to go to sleep or to go to work.
Outlander - Diana Gabaldon
Another comfort read that includes some very unpleasant scenes. But the thing is, I know they're there, and I know it all works out in the end, so it doesn't matter terribly that I have to read them.
Again it's a book that draws me in completely. Again it's a book with humour and romance, and again it's a book that offers nice descriptions of how people lived, worked, cooked etc. Apparently such descriptions often occur in my comfort reads ;)
I was very, very unimpressed by the latest kerfuzzle surrounding the author and her views on fanfiction, and lost a lot of respect for her because of that. However, I love the books separate from my feelings about the author, so this still counts as one of my comfort reads.
The Yada Yada Prayer Group - Neta Jackson
This is probably one of the most comfortable comfort reads on my list. Reading this book (well, the entire series actually) is like coming home. I love the characters and am interested in their lives. These books have done more for my Christian life than any other book I've ever read - non-fiction and fiction both - and yet, despite being challenging, they're also comforting, and I'll happily dive into one and not come out of it again until the last page has been turned.
Alanna - Tamora Pierce
The Song of the Lioness was my introduction to fantasy (other than Narnia), so even if nothing else, I'd have to love it for that. Thankfully, the book itself turned out to be wonderful, and quickly made its way to being one of my favourites, and being a lovely comfort read.
Like I've already mentioned, I like descriptions of a person's life - this goes double for life at school (which you'll also see from the next book), so following Alanna's education is absolutely fascinating to me.
Dragonsinger - Anne McCaffrey
One of my very first internet friends recommended Harper's Hall trilogy to me. Fortunately the library had it, so I got them out, and was immediately hooked! Life at Harper's Hall was extremely fascinating to me, and I so desperately wanted to go there myself (even if I'm no where NEAR musically talented enough, but ah well). Humour - check, friendship - check, descriptions of school life - check, evil people getting their just desserts - check, lots and lots of lovely music - check. Oh, and it's short enough that I can read it in just over an hour. That's not a requirement for a comfort read (as you can see from some of the other books on this list), but it does make it handy for when I don't want a long dive, but just a quick dip.
Chronicles of Narnia - C.S. Lewis
Another series where I really can't pick just one. The Lion, the Witch and the Wardrobe is probably my favourite, but it's also the one I know the best, so I don't have the same need to reread it. I LOVE the part of Prince Caspian where the children first realise they've come back to Narnia, but the rest isn't as terrific. Voyage of the Dawn Treader is just lovely, but I miss Peter and Susan.
But they're all comfort reads. Lucy, Edmund, Susan, Peter, Caspian, Tumnus... they're all old friends, and I fully expect Heaven to be something like Narnia - talking animals and all! :)
Singularity - William Sleator
If Alanna was my introduction to fantasy, then this was my introduction to sci-fi. It's not your standard comfort book, as the plot itself is rather uncomfortable in places, but I'd still rate it as such, because of my familiarity of it. Also, I like that it makes me think, and the way it draws me into the universe so completely, that I occasionally have to shake myself to get back to reality and that I have just lived a year in the span of a night.
My love for this book cannot be explained. It's completely unlike most books I love, but it's fantastic.
The Rosary - Florence L. Barclay
No list of comfort books would be complete without a mention of The Rosary. I think this is possibly the most beautiful book I've ever read. The plot is fairly standard, and while both sweet and romantic, it's of the type that's a dime a dozen. No, it's the writing that really makes this book. Ms. Barclay has a way with words that is unlike almost any other I've ever encountered (with the possible exception of LMM).
So add beautiful writing, amusing scenes and a romantic story and you end up with a very happy Maria :)
I've stayed away from Danish books, as most people here wouldn't know them anyway. That's NOT to say there aren't some wonderful Danish comfort reads out there, and if you're able to read Danish, you should definitely go pick up some books by Estrid Ott :D