Handbook 6th edition

Looking for a designer that is better than me(!) to design a four-color textbook for both print and electronic versions. This is essentially a textbook, lots of technical wording, and I am estimating it will be 500-525 pages. I could do the entire initial layout in InDesign, which then could be modified, improved, etc. by a professional (or whatever works best). I have uploaded a previous cover.