Why did the Concorde require a droop nose and how did it work? As seen in the picture below, Concorde used to have a droop nose which would be deployed during takeoff/landing and would be retracted to the normal position while in cruise (do reduce drag).

Concorde with a droop Nose deployed

  

Concorde in normal configuration



According to the wiki page on Concorde, this Droop Nose was added in the later versions of Concorde when the authorities raised questions about the restricted view which was available to pilots during landing/take off at very high angles of attack (which was required for the Concorde).


What are the other possible solutions which could have been employed instead of the droop nose to tackle to the restricted view from the cockpit?
Why did Concorde had to land and take off at higher than normal angle of attacks?
How did the Droop nose actually work? (Which mechanism was used to deploy and retract it)
1) Though already mentioned that this might be too broad, I would dare to guess a properly fitted camera could do the trick. But I doubt that this would be effective considering the technology of the era that Concorde was developed.

2) Concorde due to its design for supersonic speeds, it was generating too little lift at low speeds (like those needed for landing). So they had to take into advantage another way of producing lift: vortex lift. In order to produce vortex lift, you need relatively high angles of attack and consequently high pitch attitude.

3) I cannot answer this since I am not an engineer. Though with little googling I found this. It seems to be very detailed, with photos of the lever and diagrams of the mechanism.