feat: book added (#11787)

books/free-programming-books-subjects.md

@@ -945,6 +945,7 @@ Kerridge (PDF) (email address *requested*, not required)
 * [Category Theory for Programmers](https://github.com/hmemcpy/milewski-ctfp-pdf) - Bartosz Milewski (PDF)
 * [Delftse Foundations of Computation](https://textbooks.open.tudelft.nl/textbooks/catalog/book/13) - Stefan Hugtenburgand, Neil Yorke-Smith @ TU Delft Open (PDF)
 * [Homotopy Type Theory: Univalent Foundations of Mathematics](https://homotopytypetheory.org/book/) (PDF)
+* [Introduction to Theoretical Computer Science](https://files.boazbarak.org/introtcs/lnotes_book.pdf) - Boaz Barak (PDF)
 * [Introduction to Theory of Computation](https://cglab.ca/~michiel/TheoryOfComputation/) - Anil Maheshwari, Michiel Smid (PDF)
 * [Models of Computation](https://cs.brown.edu/people/jes/book/) - John E. Savage
 * [Principles of Programming Languages](https://web.archive.org/web/20150418034451/http://www.cs.jhu.edu/~scott/pl/book/dist/) - Scott F. Smith *(:card_file_box: archived)*