“For a painter whose reputation is based in part on his systematic approach to serial imagery, his [Monet’s] sketchbooks offer a startling glimpse into another side of his artistic personality. If there is anything deliberate about these books, it is the very casualness with which he filled them in, throwing them open almost at random, continuing studies across the binding, and paying little attention to composing each page.
“… For many of the drawings, Monet held his sketchbooks vertically like a flip pad rather than horizontally like a book. … Monet did not recognize a primary orientation in his sketchbooks; to him they had no front or back, no up or down.”James a Ganz and Richard Kendall, “The Unknown Monet: Pastels and Drawings”, page 169
It’s your sketchbook, you make the rules for it.