Suggest me a book like Sphere by Michael Crichton… but better

I loved the set up in this book. The idea, the setting and the first half were so much fun, just like some of the other Michael Crichton books I've read… but I felt like it floundered after a while. I still enjoyed reading it but the excitement and intrigue I felt at the beginning was never fully satisfied.

Now I'm left wanting more. Can anyone recommend a book in a similar vein?

Thanks!