I am grateful to Oxford University Press for their permission to include here the following three extracts from the volume itself as pdf files.

The first is the Preliminary material. This consists of pp. vii--xxx and includes the Contents, Preface, the Note on the Texts, and the Note on the Translations. The whole collection of translations has been divided into three parts. For each of the three groups of translated works there is a separate introductory section that offers some specific background material and context for the individual works of that group. In addition there is a general Introduction to the collection as a whole.

Also included is the complete first work, published in 1804, which was Bolzano's own doctoral thesis and his first published work. It forms the first of the group under the general title of GEOMETRY AND FOUNDATIONS. The introductory section to this group contains significant background material to this first work but it is not included among these extracts. The first work is abbreviated BG because of its German title and has the full English title: Considerations on Some Objects of Elementary Geometry