I purchased this book to get an overview of the important authors and movements in English literature. From Beowulf to the 21st century, all the important authors and works are included. But the most rewarding part about the book is that it does a fantastic job of putting the important authors and movements in their historical context.
For example, Shakespeare is significant not only because of the genius of his plays but because they reflect Britain's transition from the Middle Ages to the Early Modern period. And instead of simply stating how great an author Jane Austen is, this book explains the importance of her works appearing on the eve of the Industrial Revolution in Britain.
The book also does a great job of summarizing and breaking down major works (like Robinson Crusoe, typically viewed as the first "true" novel) as well as major authors (Wordsworth, Austen, Lord Byron, Pope, Swift, etc.), dedicating as much as three pages detailing a single poet or major work. Even if you haven't read classics like Rime of the Ancient Mariner, Paradise Lost or The Faerie Queene, you'll feel like you did after reading this book. This is a fantastic book I will refer back to for many years, perhaps decades, to come.
By the way, Amazon's description is incorrect. The book is roughly 290 pages (not including the index), not 500+.