I had vague memories of the PBS series from years ago and looked forward to reading this. I was not disappointed. The book was published in 1945, begins in that year, then jumps back 20 years to cover "The Sacred and Profane Memories of Captain Charles Ryder" - the subtitle of this book. The "sacred and profane" are key words - this book is about religion, in general, and Catholicism, in particular, and its affects on the aristocratic Flyte family, their friends, and lovers. The writing is delightful, the characters engaging, and the love story tragic. Highly recommend this one. 
 Edit: 
 I featured this book in an article about a trip to Tuscany. Here's the excerpt dealing with this book: 
 "From Florence we wandered the countryside. Like the 19C English tourists in My Cousin Rachel we visited hilltop towns that had changed little from the Middle Ages, watched stunning sunsets over the Tuscan hills, tasted the local wine, and ate the local delicacies. We even took a side trip to Ravenna--a favorite destination for those on the "Grand Tour" (and mentioned in the book I'm currently reading Brideshead Revisited. There, we admired the 5C mosaics at the Mausoleum of Galla Placidia (the protagonist in my second book), biked the cobblestone streets (a jarring experience!), and ate divine gelato." 
 The full article can be found here.