Yeah Essential's more aimed for underclassman (e.g., sophomores) whereas the other text is for upperclassman (i.e., juniors and seniors) and graduate students.

Yeah Essential's more aimed for underclassman (e.g., sophomores) whereas the other text is for upperclassman (i.e., juniors and seniors) and graduate students. It's probably more useful for laymen. Those who find themselves wanting more can always go to the larger, more comprehensive text later.