Path Tracing

Ray Tracing in One Weekend series

Series of online books teaching the basics of path tracing

Beginner Friendly
Ray Tracing/Overview
book
tutorial
c++

Lecture 18: Monte Carlo Rendering (CMU 15-462/662)

An introduction to Monte Carlo ray tracing

Randomness/Monte Carlo
video

The rendering equation

The classic Kajiya rendering equation paper introduced the "rendering equation" and the path tracing algorithm

PBR/Light Transport
Randomness/Monte Carlo
paper
classic

Robust Monte Carlo Methods for Light Transport Simulation

the Academy Award-winning Ph.D. thesis by Eric Veach. It starts from bidirectional light transport algorithms and introduces multiple importance sampling and Metropolis light transport

PBR/Light Transport
Randomness/Monte Carlo
Randomness/Variance Reduction/Importance Sampling
paper
classic