I didn't know that Physically Based Rendering was introduced as a book, and that book is a literate program (as in, you can compile the book and get a physically based renderer as a binary) that was so influential that it received an academy award(!).<p>There's a video of two famous actors announcing them, being professionals they explain exactly what the book is about convincingly despite not having a clue what they are talking about:<p><a href="https://www.youtube.com/watch?v=7d9juPsv1QU" rel="nofollow">https://www.youtube.com/watch?v=7d9juPsv1QU</a><p>In their receiving speech they give a shout out to Donald Knuth for pioneering literate programming.
Path tracer. Ray tracer implies a Whitted Ray Tracer. This is clearly using Monte Carlo sampling and BRDFs to scatter rays using multi-bounce lighting (hence paths instead of rays)