Hilbert's 1900 lecture, Gödel, Turing, and Church, etc.
Turing machines, Church-Turing thesis, decidability, halting problem, Reductions between problems, Rice's Theorem. (Sipser text, Chapters 3, 4, and most of 5 and maybe part of 6; also Wegener 2.1).
Wegener text, Chapters 1-7.1. (Lighter coverage of most but not all topics in Sipser Chapters 7 and 10.2)
Specific topics will include
Wegener, Chapters 10 and 13. (Sipser covers some of this in Chapters 8 and 10.3.)
Wegener Chapter 8; light sketch in Sipser 10.1.