We’re often told that in order to be successful in business or sports, the key is specialization at a young age. The story of Tiger Woods and his path to becoming one of (if not the) greatest golfers of all time, confirms that beginning at a young age and specializing with a narrow focus is a surefire way to success. The book Range by David Epstein turns this notion on its head and argues that breadth of knowledge is more applicable to measurable success outside of a few specific fields. The key distinction upon which Epstein’s argument is based can be boiled down to the different types of learning environments. Domains that have rules with well-defined boundaries, like golf and chess, are conducive to mastery via repetition and can be defined as "kind" learning environments. However, there are many areas in which the learning environment is "unkind," which can be characterized where rules are often unclear or incomplete, there may or may not be repetitive patterns, and feedback is often delayed. Examples of unkind learning environments are poker, investing, and major life decisions. Throughout the book, Epstein posits that not only is breadth of knowledge and experience more applicable to excelling in the modern knowledge-based economy, but that hyper-specialization can lead to “cognitive entrenchment” whereby if the rules in a kind learning environment are altered slightly, the “experts” have a more difficult time adapting to the new rules than the non-experts or “novices” do.

Epstein also explores the concept of “grit” that was created by psychologist Angela Duckworth, which is a self-assessment that combines perseverance and passion, to determine if the notion of perseverance may be misinterpreted when used in character assessments. Epstein also draws from the work of Seth Godin, who found that individuals who reach the apex of their domain “quit fast and often when they detect that a plan is not the best fit, and do not feel bad about it.” While preserving through difficulty can be a competitive advantage, knowing when to quit is such a strategic advantage that Godin suggests that “every single person, before undertaking an endeavor, should enumerate conditions under which they should quit.” This concept is something that humans struggle with, weighed down by the “sunk cost fallacy” having invested either time or money into an endeavor. To wit, a recent Gallup survey of more than 200,000 workers in 150 countries reported that 85% of workers were either “not engaged” or “actively disengaged.”

The book culminates by dissecting examples of instances where teams have performed poorly by harbouring an unwillingness to look outside of their usual “analytical toolbox,” expounding the notion that top performing teams utilize “outside-in-thinking” along with a diverse range of viewpoints and experiences to excel in their domains. Furthermore, Epstein argues that scientific research has become too specialized, citing an increased rate in retractions in scientific literature in recent years that he attributes to a lack of integration between fields. However, a study by Northwestern and Stanford researchers showed that networks which give rise to creative triumph have porous boundaries between teams, where interdepartmental collaboration is encouraged. While work that is broadly focused and builds disparate pieces of knowledge is likely to have a harder time finding funding, it is more likely in the long run “to be a smash hit in the library of human knowledge.”