The name Willy Neutken is legendary among BMW Motorrad collectors: he assembled the greatest collection of the brand's creations in the world.
Neutken worked in the family business, MotoPort Neutkens, until he was ready to pass on the main responsibilities to his son.
He then devoted all his time to collecting and restoring BMW motorcycles.
In 1998, BMW Netherlands used an exhibition of the Neutkens Collection to celebrate its 75th birthday.
That same year, Neutken was honoured by the Guinness Book of Records for having the largest collection of motorcycles by a single manufacturer.
By this stage, Neutkens's collection included an example of almost every type of bike made by BMW since it began in 1923.
Now the collection is up for auction following Neutkens's death in 2008.
Some of the best pieces available include a pair of R42s and an R47 from 1926-27. They are estimated at £18,000-22,000, £17,000-20,000 and £20,000-25,000, respectively.
An R32 from 1923 will also appear, estimated at £30,000-40,000. The R32 introduced the flat-twin boxer engine to the world.
Two R75 Kriegselefant sidecar outfits from WWII - years 1942-3 - will go on sale priced at £20,000-25,000 each. They are painted in Afrika Korps colours.
The motorbike of George Maier, the legendary Isle of Man TT-winning racer, will be a star of the show. Maier's 1953 R68 ISDT is estimated at £17,000-20,000.
The Bonham's auction will take place in Munich on November 28.
"It is a privilege to offer this collection on behalf of the Neutkins family," said Bonham's Ben Walker.
"Not only is it one of the most prestigious collections of BMW motorcycles in the world, but it is also taking place at a world class museum, The BMW Museum in Munich.