Plant biotechnology can be briefly defined as the use of developments in biological sciences with the help of technological developments for application and commercial purposes. Plant biotechnology is not actually a new concept because, according to this definition, biotechnology began with the cultivation of wild plants 10 thousand years ago. However, biotechnology has been applied differently throughout the ages. For example, after Hoagland and Arnon developed the "Hoagland Solution" in the 1950s and showed that plants could grow in a soilless environment, this solution (which actually contained 11 mineral salts important for plants) was used for many years in hydroponic vegetable growing. This was the plant biotechnology of those years. Today, advances in biological sciences and new discoveries (cell culture, cell fusion, genetic engineering) have caused the content and application of biotechnology to change and become more complex. Plant biotechnology has now become an interdisciplinary branch of science that requires the joint work of people specialized in different branches of science. Therefore, it is imperative that university students who plan to specialize in plant biotechnology in the future have a good basic education covering various areas of biotechnology. Today, plant biotechnology is taught in undergraduate and graduate level courses in many of our universities. However, since there is no Turkish reference book prepared by experts covering every area of ​​plant biotechnology, students who do not speak a foreign language have difficulty in accessing the information they want in the field of plant biotechnology. I believe that this book, which is organized as two volumes, “Plant Biotechnology I” and “Plant Biotechnology II”, will fill an important gap in this field and will be helpful to interested students and scientists. Therefore, I would like to thank all my colleagues who prepared the book and contributed with their articles, and I commend them for their efforts.