After the critical and commercial failure of Angel of Darkness, Eidos Interactive gave the Tomb Raider rights from the Core Design team, the original creators, to Crystal Dynamics, known for the Legacy of Kain series. What followed was Tomb Raider Legend, a critically well received and more profitable reboot.
Running parallel to Crystal Dynamic's production of Legend, Core began working on a remake of the original Tomb Raider, under the title Tomb Raider Anniversary. The final product would have been released for the PSP. Eidos, however, cancelled the project before it was finished (reportedly, it was over 60% done when cancelled). There are conflicting reports to why it was cancelled but the popular explanations are Eidos didn't want Core to release the game after the design team were sold to another publishing company and Eidos would prefer Crystal Dynamics to develop the game.
In 2007, Crystal Dynamics released their version of Anniversary. A playable version of Core's game has yet to be released.
Interview with two members of the Core Design team behind Tomb Raider Anniversary Retrieved 31 Oct '13
Videos and Screenshots from Tomb Raider Anniversary Core Edition Retrieved 31 Oct '13