At Balkinization, Brian Tamanaha has an interesting post on common misunderstandings of Legal Realists. It resolves some contradictions that I had never understood (in part, I had taken Jerome Frank, who is a bit of an outlier, as a typical Realist).
Llewellyn's point was that the Realists were indeed critical of mechanistic accounts of judicial decision-making—as deductive and exclusively rule-focused—but they did not commit the opposite error of suggesting that judging is purely subjective and not legally constrained. Rather, the Realists brought attention to other stabilizing aspects of the craft of law and judicial decision-making besides just the legal rules. While they denied that law was certain to the extent that formalism portrayed, they agreed that there was a great deal of certainty and predictability in law (though not attributable to the legal rules alone). They also argued that in some cases policy decisions were called for and should be done openly by judges, although they recognized that many cases were routine and determined by the legal rules.