"Linear and Nonlinear Functional Analysis with Applications" by Philippe G. Ciarlet is an excellent resource for anyone seeking a thorough understanding of functional analysis and its applications. While it may require some background in mathematics and analysis, the book is well-suited for graduate students, researchers, and practitioners in mathematics, physics, and engineering.
The book you're referring to is likely "Linear and Nonlinear Functional Analysis with Applications" by Philippe G. Ciarlet. Here's a brief review: and practitioners in mathematics
A very specific request!