[Title] "Euler's Gem, New Edition: Learning Humanity's Treasure e^iπ=-1" (Takeshi Yoshida / Author) Price: ¥1,980 (tax included) [Content] A completely self-study book with no prior knowledge required! 500 pages of powerful content inviting you to the pinnacle of mathematical beauty. Thoroughly explains the basics of mathematics, aiming to understand Euler's formula, the mysterious circle woven by Napier's number, pi, imaginary numbers, exponential functions, and trigonometric functions. The clear descriptions make it a suitable supplementary textbook for junior high and high school students. This book is a continuation of the same-titled book (final edition: 26th printing, April 2019) published by Tokai University Press in January 2010, which our company is now publishing.