We are all aware of Darwin, but the men who were instrumental in the rise of the Modern Synthesis and the banishment of the Eclipse of Darwinism are not figures who loom large in the public imagination. In the domain of population genetics they would be R.A Fisher, J.B.S. Haldane and Sewall Wright. R.A. Fisher's daughter wrote a good biography that chronicles his private and public life, Life of a Scientist. Statistically oriented people will be particularly interested his conflict with Jerzy Neyman. Will Provine's Sewall Wright and Evolutionary Biology is probably the most multidimensional single volume tome you could stumble upon which still remains accessible. Like the Holy Ghost J.B.S. Haldane is someone who I haven't really been able to put a fix on as easily, but his Causes of Evolution was worth the read (I haven't read any biographies, but Marek Kohn's A Reason for Everything spends a great deal of time on him). You can find many of the papers of R.A. Fisher at the digital archive maintained by the University of Adelaide. His Genetical Theory is a pithy, if somewhat technically opaque, exposition on his outlook on evolutionary biology. Wright's Evolution and Genetics of Populations is more verbose, as befits a less abstract and more empirical thinker. Let me finish with a quote from The Genetic Basis of Evolutionary Change by Richard Lewontin:
For many years population genetics was an immensely rich and powerful theory with virtually no suitable facts on which to operate. It was like a complex and exquisite machine, designed to process a raw material that one had succeeded in mining. Occasionally some unusually clever or lucky prospecter would come upon a natural outcrop of high-grade ore, and part of the machinery would be started up to prove to its backers that it really would work. But for the most part the machine was left to the engineers, forever tinkering, forever making improvements, in anticipation of the day when it would be called upon to carry out full production....
Lewontin was writing in the wake of his discovery that polymorphism levels were
far higher than either the Fisherian "Classical School" or the Wrightian "Balance School" would have predicted
. This spurred on the development of Neutral Theory, which holds that most substitutions of one allele for another on a locus are due to randon genetic drift operating upon mutations which do not exhibit negative or positive fitness deviations from the population mean. Today the rise of computation and incredibly powerful assaying techniques are starting to provide a great deal of raw material for the abstract analytic theoretical engine to sieve through. Hallelujah!