Out of the broad variety of Cusanus’ work, this book discusses six of his writings, careful not to isolate them from the whole of his work. It instead presents them against the maturation of Cusanus’ thinking as it developed from his first sermons up to his shortest philosophical text De apice theoriae. The texts in question are De docta ignorantia, De coniecturis, Idiota de mente, De beryllo, Trialogus de possest and De apice theoriae. In the search for God, or rather in Cusanus’ lifetime efforts to have his spirit touch the first principle and the basis of all things, new perspectives on the world and man within would open up for Cusanus. Respecting this basic intention of Cusanus’ thinking, the author primarily deals with Cusanus’ ontotheological (metaphysical) claims and, in their context, turns his attention to the cosmological, or anthropologico-gnoseological opinions.