Sequential Experiments with Primes is among the 100 Best Number Theory Books of All Time @ https://bookauthority.org/books/best-number-theory-books at #60 (Thank you! :-))
I believe the attractiveness of the book lies not only on the novelty of certain ideas, but also in the style in which said novelty is attained. It's a sort of "jazz" with numbers (unfolding as a sustained creative piece not unlike the free development of a jazz gig). A jazz with no particular rigid/studied reverence to other established theoretical
approaches. Just free self-sustained jazz discovering new facts. In its way, it's structured as a sort of "dessins d'enfants" leading to a different look on the mystery of prime numbers.