Who is John Eastman, the Trump lawyer at the center of the Jan. 6 investigation?

https://www.npr.org/2022/06/17/ [login to see] /who-is-john-eastman-the-trump-lawyer-at-the-center-of-the-jan-6-investigation
At the center of Thursday's House hearing investigating the Jan. 6 insurrection was a lawyer central to former President Donald Trump's efforts to overturn the 2020 election: John Eastman.

After Joe Biden won the election, Trump took several routes to try to overturn the election: he tried lawsuits, which failed; he tried pressuring state officials, which also failed; and he ultimately tried to get former Vice President Mike Pence to overturn the results when the electoral votes were to be certified on Jan. 6, 2021.

That last plan was drafted in a memo by Eastman.