Outline View: good for faster navigation on lap/desktops and tablets.
Page View: useful for phones (a single-column display with context-sensitive navigation at the foot of the page) and for a more web-page-like experience.
Explorer Focus View: a spatial-focus View on lap/desktops and tablets.
Use the "Views" menu to select any of these Views, and more.
Please also see the attached note on cross-links (the yellow boxes).