The lecturer is Professor Leonard Susskind and the video lectures are courtesy of Stanford University.
A second source of confusion is how the lectures are named and ordered. The subject matter in Lecture 2 & 3 comes after Lecture 7 but before Lecture 8.
It was probably videoed some time after the earlier lectures, and - noting the sarcastic comments at the beginning of the lecture- without an audience.
This course covers the mathematics of special relativity in detail. Space and time, previously thought of as independent, are combined symmetrically to form space-time by considering Lorentz transformations between inertial frames.
We shall look at kinematics, meaning how things move - time, space, velocity, simultaneity. And then we move on to dynamics, or why things move - energy, momentum, force culminating in the reformulation of the Lorentz force and Maxwell's equations so that they are invariant in all reference frames, as required if they are to be laws of nature.
We will also look at some aspects of general relativity, but not the general theory, which comes in a later course. We shall look, in particular, at the expansion of the universe.
This website has no connection or affiliation to either Stanford University or Professor Leonard Susskind.
This is one non-physicist's set of organised notes which, hopefully, may be of some use to others. Any errors in my notes are mine alone and readers should beware that they might not reflect the content of the lectures accurately.
I would very much appreciate all and any corrections, especially on any of the physics or mathematics, but I'm sure there's the odd typo or two!