Learn Spanish (Spain): El libro está aquí.

Aquí means "here" and is used when an object is right next to or very close to the person speaking. If the book were further away, you would use allí (there).

Why do we use está for "is" instead of es?

In Spanish, you must use the verb estar (where está comes from) to talk about where something is located. Because we are stating the location of the book, we use está. The other verb for "to be", ser (which gives us es), is used for things like identity, descriptions, or origin.

Why do both está and aquí have accent marks?

Accent marks in Spanish often tell you which part of the word gets the strongest emphasis when you say it out loud. For está and aquí, the stress falls on the very last syllable: es-TÁ and a-QUÍ. The accent on está is especially important because without it, the word esta means "this" instead of "is".