Melody Pond

Professor River Song is a mysterious archaeologist who shared a close relationship with the Doctor. Although the Doctor's first meeting with her ended in her death, she told the Doctor that, due to the complicated nature of time travel, he had many adventures with her yet to come.

Profile

Early Life

River Song was an archaeologist already highly familiar with the Doctor when they first meet (from his perspective) in the 51st century. She was, in fact, a future companion of his who travelled with him off and on. According to her, he trusted her implicitly. Prior to her encounter with the Weeping Angels, she was imprisoned for murder. Whether or not she was guilty is unknown. (DW: The Time of Angels/Flesh and Stone.

Crash of the Byzantium

These events happen after River has met the Doctor for the first time

Doctor River Song was a guest on the Byzantium ship, she was working for a military organisation at the time when that happened. She snuck down into the lower levels and found a cube, she then carved something in it to attract the Doctor, 12,000 years later the Doctor found it. River then managed to escape from the guards there and fly out, the Doctor prompted by this came and she jettisoned of the ship into the TARDIS. River then show exceptional TARDIS flying skills landing next to the Byzanttium which had crazed into the Maze of the Dead, home to the Weeping Angels. River along with several of her military friends went in with the Doctor. They had a recording of an Angel which Amy watch almost manifest until she managed to turn it off. In the Maze several of the party were killed and possessed by the Angels which where old and weathered away. Amy though wondered who River was. (DW: The Time of Angels)

A lot of events happen between this and her death in the Library

Death

River's expedition to the Library was financed by Felman Lux and was chartered to find out what disaster had happened there, 100 years previously, that had caused 4022 people to "die" or disappear. When her team ran into trouble during an expedition to a deserted library, it was only natural that River should try to summon the Doctor by sending him a message via psychic paper. The version of the Doctor who turned up had not yet met her. Though bewildered, he agreed to help River and her team.

File:River and 10.png

River and the Tenth Doctor "do diaries". (DW: Silence in the Library)

River and the Doctor appeared to be very familiar, even considering the strong bonds the Doctor forms with his companions. She kept a worn and battered diary which the cover looked very much like the TARDIS doors, keeping a journal of her travels with the Doctor. There was a suggestion that in the future the Doctor's personal future she would carry a similar journal, as she commenteted about needing to "compare" diaries. She carried a upgraded version of the sonic screwdriver which "her" version of the Doctor had given her. As the situation in the Library deteriorated, River realised she must prove to the Doctor that she was (or will become) someone he trusts completely and with profuse apologies, she whispers his true name into his ear. The Doctor was stunned by this information, and River succeeded in winning his trust.

River physically died when she chose to sacrifice herself in order to stop the Doctor from sacrificing himself in order to save Donna and the other 4022 people trapped in the Library. She pleaded with him to not try and change history, not to change one moment of what is to come for them.

After saving all the trapped people, the Doctor realized his future self must have given her his sonic screwdriver for a reason. Inside he found a data chip, which contains River's Data Ghost. The Doctor saved her by uploading her into the virtual world contained in The Library's data core. CAL, the library's data core controlled by a human girl wired into its mainframe, also managed to save the data ghosts of all of River's dead archaeological team, so she would have company in the virtual world. (DW: Silence in the Library/Forest of the Dead)

When Davros said to the Doctor that "Everywhere you go there are always deaths" River appeared in a flashback, as the Doctor had flashbacks over those who have died during his travels. (DW: Journey's End)

Other Information

River Song seemed to take shorter trips with the Doctor, living a more or less normal life between trips, rather than having one extended trip with the Doctor and never seeing him again after parting ways.
The Doctor indicates that there is only one event wherein he would or could tell her his true name.
Song appears to have knowledge of Time Lord anatomy, including knowledge of regeneration. She also indicates that destruction of both of the Doctor's hearts is a circumstance after which regeneration is not possible.
It is unknown precisely where in time and space River Song originally came from. As the Doctor has left previous companions in different parts of the universe from where he originally found them, it is possible that River was not originally from the 51st century at all.

Song's screwdriver

River Song's Timeline

River Song meets the Doctor for the first time.

River Song and the Doctor picnic at Asgard. (DW: Silence in the Library)

River Song and the Doctor are at the crash landing of the Byzantium. (DW: The Time of Angels/Silence in the Library)

River Song and the Doctor travel to the End of the Universe

The Doctor, with a new haircut and a suit, visits River Song and takes her to see the Singing Towers of Darillium. He gives her his Sonic Screwdriver.

River Song tries to send 'her Doctor' a message via the Psychic paper, asking him to come to the Library. (DW: Silence in the Library)

The Tenth Doctor, whilst traveling with Donna Noble comes to the Library in the 51st Century at her request and meets River Song for the first time, when they face an infestation of Vashta Nerada within the Library.

River Song proves to the Doctor how important she will be to him by whispering his true name in his ear. (DW: Silence in the Library)

River Song sacrifices herself to save the Doctor and the Library. (DW: Forest of the Dead)

The Doctor beams River Song from a Neural Relay in her sonic screwdriver into the Library's Data Core. (DW: Forest of the Dead)

River Song's brainwaves live on in the virtual world inside the Data Core, containing CAL and Doctor Moon. She is reunited in this virtual world with her crew mates, Proper Dave, Other Dave, Anita and Miss Evangelista, whose brainwaves must have also been added to the Data Core. (DW: Forest of the Dead)

Behind the Scenes

It is also known that she will have two adventures with the Eleventh Doctor in the upcoming series, both of which are two-parters: episodes 4 and 5, and the finale of episodes 12 and 13.
In a recent interview by Digital Spy, Steven Moffat made a passing comment to the effect that River Song might turn out to be very different from people's presumptions as to who she really is. [1]
River Song has been seen in several different outfits and situations in the trailers for Series 5, such as: wearing a 1920's style evening gown and floating out of the airlock of a spaceship in an apparent attempt to escape a number of human pursuers (also in 1920's clothing); in military khakis as she fights the Weeping Angels alongside the Doctor; and in a regular jacket and slacks as she explores Stonehenge with the Doctor and Amy. This heightens the confusion about where she actually comes from and how she meets the Doctor.
From the various clips of River Song released in all the trailers thus far, it can be inferred that at some point, she opens the airlock of a spaceship to escape a group of men chasing her and floats through space before being caught by the Doctor and pulled into the TARDIS. This may be how she meets the Doctor in the first place. This now seems unlikely, however, because a new clip shows her being able to pilot the TARDIS herself, and claims that the reason the TARDIS makes its materialising noise is because the Doctor leaves the breaks on, showing that she has met and traveled with him before in her timeline. She also knows more about how to pilot the new TARDIS interior than the Eleventh Doctor does.
It was revealed by Steven Moffat that River Song herself is a time traveler, hence the strange nature of her personal timeline interactions with the Doctor's personal timeline. It was revealed that, whenever she needed to, she would go to a point in time where she can interact with a past incarnation of the Doctor, fitting with an apparant comment made shortly after he debut that she had met multiple incarnations of the Doctor. The whole nature behind these meetings, however, remaings a mystery. It was also revealed that, despite the popular theory, River Song is more than just possibly the Doctor's wife. Being a time traveler and from the 51st century, some theorise that she could be a Time Agent.