Marilyn Vos Savant
Marilyn Vos Savant is an American columnist, known for being "the smartest person in the world", based on her reported IQ in the 1980s.
Published in 1990, the book contains 155 tasks aimed at strenghtening both the intellect and lifestyle.
I Forgot Everything I learned in School
Published in 1994, this book departs from what is learned through formal education, and attempts a program to regain the knowledge with a variety of exercises focusing on both specific mental skills (memory, vocabulary, reasoning, etc.), and specific topics (psychology, literature, economics,etc.)