In the preface to the first volume of the second edition, it was mentioned that the individual essential oils would be covered in a later volume. However, during the preparation of this part, it became evident that the material had more than doubled compared to before and could not be accommodated well in a single volume. Therefore, it seemed sensible to make another division and to publish the manuscript, as far as it was completed, as a second volume. The arrangement has remained the same. As in the first edition, the essential oils are listed according to their occurrence in plants, which are organized according to the system established by A. Engler in his syllabus of plant families. This volume presents the oils, including those from the Zygophyllaceae and part of the Rutaceae. A third volume will complete the work.