Tidal Locking - Why Do We Only See One Side of the Moon?

In 1959, Luna 3 revealed the moon's far side. The moon's synchronous rotation and orbit mean we only see one side. Initially, the moon's spin and orbit were not aligned, but Earth's gravity synchronized them over 1,000 years. We see some of the far side due to the moon's elliptical orbit and tilted axis, but 41% remains hidden. Satellites have mapped the unseen areas, but our view of the moon is still limited.

How did Earth's gravity influence the moon's rotation rate?

What percentage of the moon remains hidden from Earth?