This document discusses depth-first search (DFS) and breadth-first search (BFS) graph traversal algorithms. DFS explores branches as far as possible before backtracking, using a stack data structure, while BFS explores neighbor nodes level-by-level using a queue. Both algorithms have distinct uses, with DFS suitable for topological sorting and mazes, and BFS for shortest paths and web crawling. The document also covers applications in computer science, real-world domains, challenges, optimizations, and concludes that understanding DFS and BFS leads to efficient graph solutions.