Important papers and open problems in Boolean functions
Bryant's "Graph-Based Algorithms for Boolean Function Manipulation" introduced Reduced-Order Binary Decision Diagrams (ROBDDs) for representing and manipulating Boolean functions.  I believe these see a lot of use in CAD tools and circuit synthesis problems.  Bryant's paper is a good place to start a literature review for BDD.  He cites a few key earlier works and a lot of the more recent work grew out of, and cited, his paper.