This is an early work of Frances Yates, one where you can already see both her remarkable methodology and the arc of her future career.
Like some of that future work, some of what she discusses here cannot be irrefutably proven, but the web of connexion she exposes makes for an extremely persuasive argument. Here, much of the work centres around the so-called School of Night. In this, it's almost inevitable to compare it to M. C. C. Bradbrook's book of the same name, published the same year by the same publisher. Sadly, such comparison does little for Bradbrook. Using similar material, Bradbrook never approaches the thoroughness or persuasiveness of Yates.
This study shows the successful technique Yates uses: to use a single period text to open up a wider discussion of the intellectual life of a group of Renaissance scholars. Branching out from Shakespeare's play, she pulls together many texts period students should be familiar with, at least by name — John Florio's language books, George Chapman's poetry, sonnets from Spenser and Sydney — and also adds texts which are newly discovered by her or texts known to scholarship but frequently overlooked.
Her writing style is swift and lucid, and coupled with her excellent research, this creates that most rara of aves — advanced academic scholarship that is immediately engaging and informative. It behooves any serious student of Early Modern literature in England at any level to read this book, and should serve as an example to advanced students of the sort of material they should strive to create.