Hopcroft Ullman's Introduction to Automata Theory, Languages and Computation has good section on state machines and their connection to Regular Expressions
So I searched and I found that my library has a book with this exact title, but by a guy named Shyamalendu Kandar. I've read the introduction and the preface, and nothing suggests it has any direct influence or relation to the book you are describing. Maybe its just a coincidence, though it does seem slightly fishy.
With automata theory it’s useful to be pedantic. What people ordinarily mean by “regex” are in different classes of automata from regular expressions as equivalent to finite state machines. For example Perl capture groups, look ahead, and backtracking are beyond what a finite state machine or its equivalent regular expression is capable of. Though for me the simplicity of the FSM is a big part its intellectual appeal.