chemical substances. The opening of the book includes both a translator’s and author’s preface, where Mendeleyev expresses his intent to harmonize experimental data with theoretical insights, fostering a deeper understanding of chemical principles. He reflects on the evolution of chemistry from observational practices to its establishment as a systematic science, highlighting the importance of historical figures like Lavoisier in framing the principles that underpin it. Mendeleyev's aim is to encourage a spirit of inquiry and experimentation among students, illustrating his conviction that chemistry not only reveals the nature of material substances but also serves practical humanitarian purposes. (This is an automatically generated summary.)