The book you are holding in your hands is believed to help you meet the multiple and high demands of the Biology course for the Orientation of Positive Studies and excel in the Panhellenic Examinations.

The material is organized into teaching units, so you can delve into one topic before moving on to the next. Each unit includes:

- Detailed presentation of the theory, enriched with diagrams that help in understanding particularly demanding points.

- Excerpts that are outside the syllabus but help in understanding the theory and avoiding rote memorization. These excerpts are marked with a gray line on the side of the page.

- Important definitions within a colored frame.

- Methodology for solving exercises. You can easily spot it in the exercises by the presence of a pink line on the side of the page.

- Detailed solved exercises and suggested exercises. The exercises that were exam topics up to 2017 have been included, as well as some topics from OEF. Several exercises were structured based on topics from the Panhellenic Biology Competition, as in the last four years many exam topics were based on this competition.

- Development questions, as well as critical-combination questions.

- True-false and multiple-choice questions, aimed at consolidating details of the theory.

At the end of the units corresponding to a chapter of the school book, there are evaluation criteria to check the knowledge you have acquired.

At the end of the book, there are evaluation criteria for the entire syllabus, answers to the questions in the school book, as well as detailed answers to all the questions, exercises, and evaluation criteria included.

It would be remiss not to mention the substantial contribution of colleague Demosthenes Avgerinos to the excellent publication of the book.