A literary critique particularly, or literary criticism generally, is a human activity (but see next paragraph) that aims to discover, analyze, describe or reveal texts or things about texts. Texts may include soup can labels, graffiti, fiction and nonfiction books, magazine articles, ads, manuals and any other written material. Because it is written, text is literature, and so the right subject of literary criticism.
Insofar as another animal than a human may interact with text as text, that animal may also engage in the activity of literary criticism and produce literary critiques. All animals that engage in the activity, including humans, are called critics.
A literary critique need not be public in any way. It may remain entirely unexpressed, that is, entirely in the mind of the animal engaged in critical activity, the literary critic. Equally, a literary critique may be written, spoken, filmed, painted, or expressed in any other possible way.
A literary critique need not be concerned with what a text is about; rather, the critique may be concerned primarily with what a text is. As follows from this, a literary critique need not be concerned with textual merit nor any other evaluative aim.
In practice in academia and outside of academia, literary criticism uses well-defined, rigorous approaches to explore texts. Such approaches may be thought of as lenses, perspectives, or simply ways of 'looking at' texts. Moral, technical, normative, political, psychological, historical, semiological, cultural, and philosophical perspectives, among many others, allow critics to illuminate for themselves and sometimes others the nature and characteristics of texts in context.
Book reviews may be considered literary critiques insofar as they participate in the described activity of literary criticism. Book reviews are not, however, a much less the major form of literary criticism.
A literary critique may analyze the language used in any text; it may analyze plot, characters, etc. in a story text or a text treated as a story. A critique may praise, fault, or be indifferent to the merits, defects or quality of a text.