The thesis collects the theoretical ideas together into a practical tool called nix, a package manager which is still in use today.

You don't need to read the whole thesis for this talk! It would be more than enough to read just Part 1 (ie chapters 1 and 2). Chapter 1 states the problem and reviews previous work, including other package managers. Chapter 2 gives a brief overview of the whole nix system.

Eelco Dolstra. The Purely Functional Software Deployment Model. PhD thesis, Faculty of Science, Utrecht, The Netherlands. January 2006. ISBN 90-393-4130-3.