I read The Once and Future King for an English class early on in high school. I read it and fell in love with history, with research and with book collecting. In class in addition to discussing what happens over the course of the novel (really the series of novels) our teacher delved into the details and hidden layers of The Once and Future King. Scattered throughout the book are quotations, some in languages other than English, as well as countless references and allusions.
As we discovered and discussed these my love of the process of research as well as the process of close, textual reading (when the book is well written) was sparked. This was in the late 1980s, long before Wikipedia and Google, our research took us into many other books and reference materials.
But the full impact of The Once and Future King on my life came after the class as I followed up on some of the future details I had learned in that class. Specifically my teacher had noted that The Once and Future King was originally published as individual books which had come out years before the book now famously read in English classes across the country was published.
I was so inspired than I took myself to the Left Bank Bookstore, where I had previously bought my treasured copy of The Manual of Chess, and started a lifelong love of book collecting by working with the bookseller to over the course of the next few years to track down early editions (and eventually mostly first editions) of the individual books which later made up The Once and Future King. The individual books, which I would eventually own in both the American and English editions, as well as many other early works by T. H. White form the start of my serious book collection and remain among my most treasured possessions.
The skills I learned making sense of the details contained within The Once and Future King continue to this day. I learned how to go from a quote or allusion to references, how to peel back layers, how to research and think about history — how to move between fiction and non-fiction, myth and history.
So buy a copy and reread it, but also dive into the allusions, relish the journey of discovery, and explore for yourself the world which shaped the books.