The story of Last of the Summer Wine is one of the most remarkable in all television history. It is the longest-running comedy series in the world, spanning 37 years and 295 episodes, growing from uncertain beginnings into Britain's favourite sitcom, at its peak uniting a third of the population in laughter with its quirky and hilarious tales of three elderly adolescents getting up to mischief in the glorious Yorkshire countryside. Last of the Summer Wine made stars of a faded movie idol and two journeymen actors in middle age, as its classic trio of Bill Owen, Peter Sallis and Brian Wilde as Compo, Clegg and Foggy achieved a magical on-screen rapport - even as their relationship behind the scenes was often marked by antipathy and bitter clashes. Roy Clarke, who has written every single episode, created a comic world centred on Holmfirth with its landmarks including Sid's Cafe and the stone steps where the scruffy Compo relentlessly pursued the fearsome Nora Batty of the wrinkled stockings, and the three protagonists regularly ended up hurtling down hillsides on fantastic contraptions like three-seater bicycles or a runaway sofa. Now the definitive story of this classic comedy series has been told for the first time. Again and again, it reveals, writer and producers were forced to reinvent it as ageing cast members died or became too frail to continue - and what began as a series that gave middle-aged actors the chance to play old men eventually turned into an institution offering genuinely elderly actors an Indian summer in the autumn of their careers - with redoubtable participants like Thora Hird and Peter Sallis continuing late into their eighties. Premiering back in 1973, when British Leyland would still sell you a new Austin Allegro, it was still going out for its final series in 2010 in the world of Facebook and the iPhone. As the years - indeed, decades - went on, comedy veterans like Michael Bates, Frank Thornton, Russ Abbot and Burt Kwouk increasingly enriched the series, and were joined by guest stars of the calibre of John Cleese, Norman Wisdom, Eric Sykes and Ron Moody. Along the way, situation comedy was transformed, and a dilapidated mill town in the Pennines became a teeming tourist attraction. Featuring new interviews with cast members, producers and directors, and Roy Clarke himself, by turns funny, deeply moving, candid and revealing, Last of the Summer Wine - The Story of the World's Longest Running Comedy Series salutes not only one of the greatest of all sitcoms, but also a golden age of entertainment.