Prolog has a declarative style. A predicate definition includes both the input and output parameters, and it allows a programmer to define a desired result without being concerned about the detailed instructions of how it is to be computed. Such a declarative language offers a solution to the software crisis, because it is shorter and more concise, more powerful and understandable than present-day languages. Logic highlights novel aspects of programming, namely using the same program to compute a relation and its inverse, and supporting deductive retrieval of informa­ tion.

Prolog具有声明式风格。谓词定义包括输入和输出参数，它允许程序员定义所需的结果，而不必关心如何计算结果的详细说明。这种声明性语言为解决软件危机提供了一个解决方案，因为它比现在的语言更短、更简洁、更强大、更容易理解。逻辑突出了编程的新方面，即使用同一个程序计算关系及其逆，并支持信息的演绎检索。