Haskell is a purely functional, lazy language, originally designed as an open standard for modern functional languages. This first Haskell Report appeared in 1990, and a "standard" was adopted in 1998. But the language has evolved considerably over the years, in particular with respect to its type system, which has many novel features. Haskell has grown in popularity recently, with numerous and substantive libraries, many real-world applications, significant improvements in implementations (most notably, the preeminent Glasgow Haskell Compiler [GHC]), and a burgeoning, supportive community of users. Haskell is particularly interesting for research into domain-specific languages, concurrency, and the disciplined control of state. The high level of abstractions it provides for solving problems is unparalleled—at least, once you understand the Haskell approach to software design.

Editors' Note: This interview is based on email exchanges with Paul Hudak, John Hughes, Simon Peyton Jones, and Philip Wadler, and then integrated with a phone interview with Simon Peyton Jones.