The City of the Sun: A Poetical Dialogue between a Grandmaster of the Knights Hospitallers and a Genoese Sea-Captain, his guest.

Reviewers note the book's significant historical value, describing it as a curious time capsule offering insight into a 17th-century vision of an ideal society. Many appreciate its detailed descriptions of societal organization and the depth with which the author explores every aspect of his envisioned state. It is considered an important text for political theory and philosophy, often inviting comparison with other foundational utopian works like Plato's Republic and Thomas More's Utopia. Readers find interest in the author's challenging personal history, having written the work while imprisoned for his beliefs. The text is also praised for its radical ideas for its time, such as the critique of individual property and, in some aspects, a focus on science and reason in governance. Some also highlight its appreciation for art, architecture, and beauty, alongside a revolutionary (for its era) notion of relative equality for women in education and societal roles. Its ideas, though controversial, are acknowledged to have influenced later revolutionary and socialist thought.

Despite its historical importance, many reviewers find the book's style to be dry, academic, and lacking in narrative engagement. Complaints include the absence of compelling characters, a lack of a cohesive story, and a conversational structure that feels artificial and preachy, missing opportunities for genuine debate. The prose can be difficult to follow, repetitive, and sometimes overly didactic. More significantly, the content itself is frequently described as disturbing and problematic from a modern perspective, with some labeling it as naive, infantile, or even deeply disgusting. Critics highlight its dystopian elements, including a communist, theocratic, and eugenicist framework that enforces rigid control over personal lives, implements harsh social practices, and often views women as communal property. The heavy influence of Christian theology and astrology is also a recurrent criticism, often seen as undermining any claims of a purely rational or scientific society. Many reviewers conclude that the book falls short when compared to its predecessors, particularly Thomas More's Utopia, citing its inconsistencies, mechanical vision, and roughly designed concepts.

Ultimately, the book is best appreciated as a historical document rather than a work of engaging fiction. It is not recommended for casual reading but is considered essential for those interested in the history of political theory, utopian and dystopian literature, Renaissance thought, and the philosophical inquiries of the Enlightenment period. Readers are advised to approach it with an understanding of its 17th-century context, as many of its ideas, while groundbreaking for their time, are now considered outdated or morally objectionable. Despite its flaws and the discomfort it may provoke in contemporary readers, the work serves as a valuable basis for intellectual comparison and discussion, offering a unique, albeit controversial, perspective on ideal societies.