Forget Burns night and St Valentine's day.

All things considered, February 4 is an even more important date in the calendar. There hasn't been much fanfare, but this Saturday marks National Libraries Day, an occasion when book lovers across the UK remove their reading glasses and celebrate one of the most influential innovations of the modern world.

Such is the affection in which libraries are held, it wouldn't surprise me to see a procession of borrowers making for their favourite library this weekend carrying breakfast trays, flowers and chocolates to honour this, the mothership of Britain's intellectual achievements. I've noticed that if you talk to anyone about libraries, they are quick to regale you with stories, often dating back to childhood. That's the case, certainly, in The Library Book, an anthology of recollections by high-profile public figures, where Hardeep Singh Kohli recounts happy schoolboy days in Langside Library. It was there, one life-changing afternoon, that he encountered a loud-mouthed cockney punk who not only offered the young Sikh his first cigarette, but gave him a chance to tell the world he was a true Scot.

For Singh Kohli, "libraries are the heartbeats of communities". Millions of us would agree. And yet of late, to witness the scything of funds for new books, the reduction of opening hours, the closure of remote branch libraries and axing of mobile vans for outlying regions, you'd think these bastions of knowledge and thought were as transient or throwaway as another charity shop or superstore.

Scotland has a noble tradition of protest against library cuts, led most recently by such writers as Theresa Breslin and Julia Donaldson. Too many local authorities, however, are deaf to readers' pleas, even when the vital role a library plays in its neighbourhood is incontestable. There are heart-rending cases, as in Brent in London last year, where people staged vigils and sit-ins, gathering around their imperilled library as if at the bedside of a patient in intensive care, yet all to no avail.

Whenever libraries are shut down, the authorities are accused, quite rightly, of cultural vandalism. Once lost, a library is very likely gone for ever. There is, however, an even bigger issue at stake than that of local provision. A library is not just a practical resource or a community hub. It is also a political statement. It is the outward manifestation of a nation's commitment to free access to information for all its citizens, the tangible expression of belief in the right for everyone, from a lollipop lady's daughter to an investment banker's son, to be educated without charge. Alan Bennett extolled the idea that libraries are not just for the hard-up in his novella, The Uncommon Reader, where the Queen begins to use a mobile library that has parked outside Buckingham Palace – "Is one allowed to borrow a book? One doesn't have a ticket?"– and finds her life blossoming as a result.

And yet the idea persists, in certain ignorant quarters, that going to the library is something you do only if you haven't got a bean to spare. It's like Margaret Thatcher's fatuous credo that any man who finds himself on a bus after his mid-twenties is a failure, as if using public services is an admission of mediocrity, or worse. Added to which, as the price of books has steadily fallen, and the ease of ordering titles online means you need never again step outside the door, some readers have forsaken their first literary home. A few, in fact, recoil from touching a book a stranger has used, as if contagion lurks on every page.

Given the dangers that beset libraries, this weekend is a good time to renew and refresh our reading habits. Those of us who take libraries for granted should set ourselves a quota of books to borrow each month. Not only will our literary horizons expand and deepen, but we will be cementing another brick into the wall of the most civilised and civilising institution the world has ever known. We will benefit, as will our communities. And a generation we'll never meet will one day have reason to take off their reading glasses, and silently thank us.