Mark Pagel is an evolutionary theorist with interests in mathematical and statistical modeling of evolutionary processes. His current interests include language and cultural evolution, networks, regulation, emergence of complex systems, robustness and evolvability, punctuational versus gradual evolutionary change, and evolutionary genomics. His co-authored 1991 monograph on comparative statistical methods in evolutionary biology is standard reading for the field and he is the author of several other statistical methods for identifying and analyzing evolutionary trends and for inferring phylogenetic trees. Some of his recent papers have reported the first evidence for regular punctuational episodes of change at the molecular level associated with speciation events. He has also used statistical methods to reconstruct features of dinosaur genomes, and to infer ancestral features of genes and proteins. Mark has identified simple rules for the assembly of protein interaction networks and speculated on their role in producing robust and evolvable systems. Most recently, he has published the first general linguistic theory to explain variation in rates of lexical evolution.