An innovative construction programme will maintain as much as possible of the existing main stand in operation throughout the contract.
The first phase will involve adding a third tier to the Main Stand, adding 8,300 seats, taking Anfield capacity to around 54,000 in time for the 2016-17 season.
The Anfield Road Stand will then be expanded to add a further 4,800 seats.
Matches will continue to be played at Anfield during the construction work.
The project will also include additional conference and banqueting facilities, a new club shop and more car parking.
The stadium expansion is just one element of a major £260m regeneration plan for the Anfield area.