There have been some extraordinary successes in the den - and of course some crushing disasters.
By Dominic Bird
Levi Root is running a big operation
But what happens after the handshakes when a deal is struck? And for those less successful, where next after the final Dragon has uttered those dreaded words: "I'm Out"?
The reality is that what happens next reflects the real business world surprisingly accurately. In business, roughly a third of proposed deals fall through before completion.
The Dragons' hit-rate compares favourably - and over the previous two series more deals have come to fruition than ever before.
But signing up to the deal is of course just the beginning.
Making money from the venture - even when you own 40% of a business - is every bit as tough for the Dragons as it is for the rest of the business community.
A venture capitalist will tell you that if they get one big money-making investment to cover nine other deals that never hit the big time, they would be happy.
Peter Jones and Richard Farleigh have reason to be pleased with their investment in Levi Roots, the Rastafarian singer behind Reggae Reggae Sauce.
He came into the den with a guitar, a couple of bottles of jerk sauce he had made in his kitchen - and absolutely nothing else, at least not of any apparent business value.
But the Dragons sensed an opportunity in the charismatic Levi, and only months after they shook hands in the den the sauce hit the shelves of one of Britain's biggest supermarket chains.
They now claim to have sold more than half a million bottles and Levi has gone from making sauce in his kitchen to running an impressive and profitable company.
It is an extraordinary tale, and the kind of story that surely inspires a thousand other hopeful entrepreneurs.
No more work
Of course, some deals fall by the wayside.
All five Dragons pledged investment in the Standby Saver, a seemingly unique plug-like device for cutting the power wasted by appliances when left in standby mode.
But the original deal was based upon a patent that the inventors Peter Ensinger and David Baker needed to protect their product.
In the end the situation could not be resolved and their deal fell through.
But that is not the end of the story.
Peter and David subsequently found another investor to buy into the product, and while Peter will not reveal exactly how much he made from the deal he does tell us he never needs to work again, which sounds like a pretty satisfying outcome - from his perspective at least.
And what of those plucky entrepreneurs who were sent from the den scorched by the fearsome words of the Dragons?
Jacquie Edwards does not accept her idea was a flash in the pan
There is surely no better evidence of the stamina of a genuine entrepreneur than this series of Where Are They Now?.
Remember Peter Ashley and his Easyxchair, a multi gym hidden in a lounge chair, which reduced the usually stoic Duncan Bannatyne to tears?
Unabashed, he is now refining his new office chair multigym - complete with hydraulics.
"This one," he says earnestly, "will be a winner".
We shall see.
You may wonder what became of Jacquie Edwards and the disposable toilet seat covers that Deborah Meaden disliked so much.
As Peter Jones would put it, her bid for investment in the den went swiftly down the pan.
But did the experience dampen her own enthusiasm for the product?
Well, the fact that she has just ordered a container-load of thousands of new improved toilet seat covers, convinced she will find someone willing to buy them from her, suggests not.
And remember Paul Simpson who wanted backing for his handmade 14th Century castle replica coffee tables.
Has he quit the replica castle-cum-coffee table game and got himself a steady job?
Of course not.
Instead he is bringing out his new table, this time a replica of Windsor castle.
And that is the point, really. For a real entrepreneur, it is in the blood.
If our dragons invest in them, there is a pretty good chance they will make it. But if they leave the den empty handed, the determination to make it on their own is as great as ever.
Watch clips of Levi Roots and the other inventors or apply to be on the programme at the Dragons' Den website (See link at the top right of the story).
Dragon's Den: Where Are They Now continues on BBC Two at 8pm on Thursday 26 July, as well as on 1 and 2 August.