The book “This is Useful and Interesting to Know” is a kind of mini-encyclopedia that will help the reader while away his leisure time with benefit and interest. The author of the book, a doctor by profession, offers the reader the most incredible, including little-known facts that will help the reader broaden his horizons. On the pages of the book, the reader will find wise sayings, useful advice, interesting scientific facts collected by the author over the past 25 years, as well as business ideas that will allow you to open your own business from scratch, without starting capital (or with minimal investment) and succeed in it . I hope that the book will become a reference book for many and will help raise your level of awareness in a short time. The book is intended for a wide readership.