A Gnostic is a person who believes that salvation is gained through the acquisition of divine knowledge or gnosis.

Gnosticism is the teaching based on Gnosis, the knowledge of transcendence arrived at by way of interior, intuitive means.
Although Gnosticism thus rests on personal religious experience, it is a mistake to assume all such experience results in Gnostic recognitions. It is nearer the truth to say that Gnosticism expresses a specific religious experience, an experience that does not lend itself to the language of theology or philosophy, but which is instead closely affinitive to, and expresses itself through, the medium of myth. Indeed, one finds that most Gnostic scriptures take the forms of myths. The term "myth" should not here be taken to mean "stories that are not true", but rather, that the truths embodied in these myths are of a different order from the dogmas of theology or the statements of philosophy.
All religious traditions acknowledge that the world is imperfect, but where they differ is in the explanations each offer to account for this imperfection and in what they suggest might be done about it. Gnostics have their own view of these matters: they hold that the world is flawed because it was created in a flawed manner.
Gnosticism begins with the fundamental recognition that earthly life is filled with suffering. In order to nourish themselves, all forms of life consume each other, thereby visiting pain, fear, and death upon one another (even herbivorous animals live by destroying the life of plants). In addition, so-called natural catastrophes like earthquakes, floods, fires, drought, and volcanic eruptions bring further suffering and death in their wake. Human beings, with their complex physiology and psychology, are aware not only of these painful features of earthly existence, but they also suffer from the frequent recognition that they are strangers living in a world that is flawed and absurd.
Gnosticism, resurfaced in the twentieth century in the forms of Theosophy, Christian Science, some forms of Spiritualism, and in what was called the "New Theology."