Gilbert Slater was an English economist and social reformer of the early 20th century.

Gilbert White was a "parson-naturalist", a pioneering English naturalist, ecologist, and ornithologist. He is best known for his Natural History and Antiquities of Selborne.

Giles Jacob was a British legal writer whose works include a well-received law dictionary that became the most popular and widespread law dictionary in the newly independent United States. Jacob was the leading legal writer of his era, according to the Yale Law Library.

Giordano Bruno was an Italian philosopher, poet, cosmological theorist, and Hermetic occultist. He is known for his cosmological theories, which conceptually extended to include the then novel Copernican model. He proposed that the stars were distant suns surrounded by their own planets (exoplanets), and he raised the possibility that these planets might foster life of their own, a cosmological position known as cosmic pluralism. He also insisted that the universe is infinite and could have no center.

Giorgio Vasari was an Italian Renaissance painter and architect, who is best known for his work The Lives of the Most Excellent Painters, Sculptors, and Architects, considered the ideological foundation of all art-historical writing, and still much cited in modern biographies of the many Italian Renaissance artists he covers, including Leonardo da Vinci and Michelangelo, although he is now regarded as including many factual errors, especially when covering artists from before he was born.

Giosuè Alessandro Giuseppe Carducci was an Italian poet, writer, literary critic and teacher. He was very noticeably influential, and was regarded as the official national poet of modern Italy. In 1906, he became the first Italian to receive the Nobel Prize in Literature. The Swedish Academy's motivation was that "not only in consideration of his deep learning and critical research, but above all as a tribute to the creative energy, freshness of style, and lyrical force which characterize his poetic masterpieces."

Giovanni Boccaccio was an Italian writer, poet, correspondent of Petrarch, and an important Renaissance humanist. Born in the town of Certaldo, he became so well known as a writer that he was sometimes simply known as "the Certaldese" and one of the most important figures in the European literary panorama of the fourteenth century. Some scholars define him as the greatest European prose writer of his time, a versatile writer who amalgamated different literary trends and genres, making them converge in original works, thanks to a creative activity exercised under the banner of experimentalism.

Giovanni della Casa was a Florentine poet, diplomat, clergyman and inquisitor, and writer on etiquette and society. He is celebrated for his famous treatise on polite behavior, Il Galateo overo de’ costumi (1558). From the time of its publication, this courtesy book has enjoyed enormous success and influence. In the eighteenth century, influential critic Giuseppe Baretti wrote in The Italian Library (1757), "The little treatise is looked upon by many Italians as the most elegant thing, as to stile, that we have in our language."

Giovanni Francesco "Gianfrancesco" Straparola, also known as Zoan or Zuan Francesco Straparola da Caravaggio, was an Italian writer of poetry, and collector and writer of short stories. Some time during his life, he migrated from Caravaggio to Venice where he published a collection of stories in two volumes called The Facetious Nights or The Pleasant Nights. This collection includes some of the first known printed versions of fairy tales in Europe, as they are known today.

Giovanni Gentile was an Italian philosopher, educator, and politician. Described by himself and by Benito Mussolini as the "philosopher of Fascism", he was influential in providing an intellectual foundation for Italian Fascism, and ghostwrote part of "The Doctrine of Fascism" (1932) with Mussolini. He was involved in the resurgence of Hegelian idealism in Italian philosophy and also devised his own system of thought, which he called "actual idealism" or "actualism", which has been described as "the subjective extreme of the idealist tradition".