Doctor Who has been around in many forms of published media for almost fifty years.
Originally starting as a television serial in 1963, Doctor Who has gone on to have almost one thousand televised episodes, over two hundred audio adventures and close to four hundred novels and then some.
Like anything else of popularity within the world of such a rich universe, Doctor who has also had its fair share of spin-offs.
The question of where or not have Doctor Who spin-offs been successful r not can be argued.
The very first Doctor Who spin-off came in 1981 in the form of a one off special entitled 'K9 and Company'.
This series would see the pairing of two of the most popular companions in Doctor Who history; that being roving female journalist, Sarah Jane Smith and the mechanical yet cute robotic dog, known only as K9.
The two had never once met on the actual program but were paired together as Sarah Jane discovers a replica of K9 left for her in her attic by the Doctor.
Together the two would team up with Brendan Richards, a ward of Sarah Jane's Aunt Lavinia and solve mysteries.
Sadly, the trio only ever solved one mystery on screen - 'K9 and Company' was not well received.
For the next twenty five years there would never be an attempt at a Doctor Who spin-off - not till the series Torchwood.
Torchwood would see its first appearance in the second season of the newly revived Doctor Who television series as a clandestine organization high up in the British Government.
Torchwood's whole existence was to hunt the Doctor.
The Doctor in his tenth incarnation brought Torchwood to its knees but Torchwood would continue to live on under the control of the Doctor's former short lived companion, Captain Jack Harkness.
Captain Jack forms a new Torchwood which is based in Cardiff and they hunt down alien threats to Earth.
A rather successful series, Torchwood has had four seasons, countless novels and audio adventures.
It has even been produced for a season in America.
The second most recent Doctor Who spin-off is 'The Sarah Jane Adventures'.
Once again we see Sarah Jane and her trusted robotic canine companion team up with a group of children who solve alien mysteries.
The Sarah Jane Adventures was a Doctor Who spin-off aimed completely at children.
It was an instant success in 2006.
However the series was cut short by the tragic death of actress Elizabeth Sladen who plays Sarah Jane Smith.
The producer of the series, Russell T Davies, has stated that he had no intention of stopping the series until this event.
This could only leave one to believe that the Sarah Jane Adventures was indeed very popular.
So there you have it, have Doctor Who spin-offs been worthwhile? Not always, but on the whole they have largely been successful.