Buddenbrooks may be the precociously brilliant debut, Death in Venice the small-but-perfectly-formed novella, but for me, Mann's real masterpiece is his sprawling snowbound epic of 1924, The Magic Mountain. Set in a tuberculosis sanatorium during the years immediately prior to the Great War, this book is many things: a modernist classic, a traditional bildungsroman, a comedy of manners, an allegory of pre-war bourgeois Europe, and – perhaps most importantly this time of year – the ideal book to keep you company on the long winter nights, when whichever flu bug is doing the rounds has gained the upper hand and forced you into a sneezing retreat to your sickbed.

For The Magic Mountain is a work of sick-lit par excellence: a novel that convincingly portrays illness as a state of mind as well as of body (though Mann does not shy away from the more visceral aspects of the latter). This is a novel mystifyingly overlooked by Virginia Woolf in her 1926 essay On Being Ill, in which she bemoans literature's failure to make illness one of its "prime themes" alongside "love and battle and jealousy." Well, here illness is decidedly centre-stage, and the plot – what there is of it – almost incidental: Hans Castorp, a naive young engineer, travels to the International Sanatorium Berghof high up in the Swiss Alps to visit his ailing cousin, Joachim Ziemssen. What was intended as a stay of a few weeks stretches into months, and then years, as Hans himself is diagnosed tubercular and dutifully takes his place among the cast of coughing consumptives. There is a chilling ambiguity as to just how much of Hans's illness is genuine and how much the result of "going native". Indeed, Hans positively revels in his status as one of the "horizontal":

Hans Castorp stayed out on his balcony, looking down on the bewitched valley until late into the night… His splendid lounge chair with its three cushions and neck roll had been pulled up close to the wooden railing, topped along its full length by a little pillow of snow; on the white table at his side stood a lighted electric lamp, a pile of books, and a glass of creamy milk, the "evening milk" that was served to all the residents of the Berghof in their rooms each night and into which Hans Castorp would pour a shot of cognac to make it more palatable.

Ensconced in his lounge chair, miles away from the cut and thrust of life on the "flat lands", Hans finds himself questioning long-held notions of honour and mortality. Up here, the snow is "eternal", and time itself becomes slippery and can no longer be trusted to behave as one would expect. This is indeed another world: of never-ending soup and ritualised – almost fetishised – thermometer readings; of rest cures and lectures on love-as-a-disease; of petty rivalries and giddy flirtations (after all, these are individuals "feverish, with accelerated metabolism"); where death is the elephant in every room and only ever happens "behind the scenes". This gives the novel a lovely feeling of the sublime and the uncanny. Indeed, at times it almost slips into the realms of the supernatural. An x-ray machine, a visit to the cinema and a gramophone player are all treated with suspicious wonder; a central chapter, entitled "Snow", concerns its 50-odd pages with Hans's near-fatal expedition into the snowy wasteland surrounding the sanatorium, an expedition that culminates in a horrific hallucination which could have come straight out of the pages of HP Lovecraft. There is even a séance scene. (And I assume we're all in agreement here that any self-respecting Winter Read should have at least one séance scene?) All the while, unbeknownst to the inhabitants of the clinic, Europe inches towards a war that will destroy this rarefied way of life for ever.

If this all sounds a little grim, it is worth reiterating that The Magic Mountain is essentially a comic novel – albeit a comic novel dealing with the darkest of subjects. The entire work is suffused with a sly and gentle humour, making it an absolute delight to read. And, if you want to make the experience more delightful still, be sure to invest in the superior John E Woods translation, published – in hardback only, unfortunately – by Everyman's Library. What it loses in the beautiful cover artwork of the paperback it gains in lucid prose-style and readability. A book I return to every couple of years, The Magic Mountain is simply one of the greatest novels ever written. And an essential purchase for every sickbed this winter…