Reference request (famous mathematicians for High School)

It's quite difficult to find maths books written by famous mathematicians of the past that even contemporary mathematicians would find worth reading from a mathematical point of view, since mathematicians write for their peers, who have both different knowledge and different interests from people of today. On the other hand, presumably mathematicians writing about stuff that isn't mathematics is not quite what you have in mind.

• Hardy, A Course in Pure Mathematics. Yes, it's an analysis textbook, but it's written by one of the English mathematicians of the twentieth century.

• Littlewood, A Mathematician's Miscellany. This is one of those books that you either really enjoy, or don't connect with, but a lot of mathematicians praise it highly.

• Hilbert and Cohn-Vossen, Geometry and the Imagination. I wish more mathematicians wrote books like this: it's a nice classical bridge from Euclidean to advanced geometry, with plenty of illustrations.

• An introduction to the theory of numbers by G.H. Hardy and E.M. Wright
• Number theory. An approach through history and Number theory for beginners by André Weil
• Solving mathematical problems. A personal perspective, Terence Tao
• Calcul des probabilités by Henri Poincaré (in french)

I recommend a classic from one of our greatest, published in 1748, with accessible content and wonderful to read

Introduction to the Analysis of the Infinite

by Leonhard Euler.