In the 1920s, William Carlos Williams wrote, "So much depends upon a red wheel barrow," and Virginia Woolf wrote, "So much depends[...]upon distance." And indeed much of To the Lighthouse reads like imagist poetry, especially Part I. It's hard to get much purchase in Part I, so heavily rooted in the inner life, dialogue, & world of characters it is. It also concerns the briefest passage of time yet is comprised of the greatest number of pages.
Perhaps fortunately then, each one of the three parts of this book is rather differently written from the next. If I had to reduce each part to a blurb—and I absolutely do think one could read each of the three parts of this book as a standalone—I would say that To the Lighthouse is, in order, one part imagistic poem, one part short story, & one part elegy. And that might be the most succinct review you'll ever get from Classic Bitch.
The book is considered Modernist and the writing 'experimental.' There is no omniscient narrator to guide us to the lighthouse. It's a dreamy, at times befuddling, elegiacal read.