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What was important about Gottlob Frege’s 1879 book Begriffsschrift?

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logic: universal affirmative — Modern logic Representations of the universal affirmative, “All A's are B's” in modern logic.

Gottlob Frege’s 1879 book, Begriffsschrift ("Conceptual Notation"), is widely considered the finest single work on symbolic logic produced in the 19th century. Its significance lies in several key contributions to the field:

First-Order Predicate Logic: The volume provides a rigorous presentation of what is now recognized as first-order predicate logic, featuring a careful and innovative use of quantifiers and predicates.12
Logic as Language: Frege treated logic as a universal medium of communication—a lingua universalis—rather than merely a tool for inference (a calculus ratiocinator). This perspective influenced later philosophers, including Bertrand Russell and the early Ludwig Wittgenstein.32
Foundations of Logicism: The work laid the groundwork for Frege’s later research program, known as logicism, which sought to derive or reduce all of mathematics to basic logical laws.12

Although its unique, two-dimensional notation limited its initial readership, the book’s painstaking rigor established Frege as a foundational figure in the axiomatic tradition of logic, profoundly impacting modern mathematical and philosophical thought.12