Sat Nam! (literally "Truth Name"--a Sikh greeting)
Your book, if it's as good as you say, would interest an agent, and an agent can get you a better deal with better publishers than you can get on your own. In fact, there are a bunch of big time publishers that won't touch you if you don't have an agent (or happen to know one of the editors).
To find an agent: Your book is narrative non-fiction, so you'll need a proposal. There are a bunch of books on the topic. One good one is by Elizabeth Lyons. Write a good proposal. Don't say your book is great. Show why it's important. Also write a good query. Unfortunately, the information on queries on this site is geared heavily to fiction. What you do is write a good query letter, giving all the details: the wordcount, the title, the genre, the fact that it's written. Do not mention your editors. (Unless they give you referrals.) State why you're the people to write the book. Make your query and proposal professional.
Then check through querytracker for agents who take your kind of book. Read the agents' websites carefully and follow those directions.
Best of luck.
Blessings,
Siri Kirpal