The English language, in particular its spelling, is a strange and wonderful beast. Essinger gets to the heart of it in Spellbound. There are many facts that won't be a surprise to most reading the book, such as much of the language being influenced by the mix of Anglo-Saxon with Norman French or the borrowing of words from other cultures as they are encountered. It's the information beyond the facts, which have obviously been well-researched, that gives the book its flavor.
Yes, it is a book about spelling, and if anything ever was a bane of school children, it could be that. Essinger approaches it with a delight and joy that is contagious. As I read the book, there were points in it where I literally laughed out loud because of the wit and humor in the pages. At other times, I felt awe and wonder that the English language ever came to be. Something that many people think is a dry subject comes alive in the book. As the author writes in the Introduction, it becomes magical.
The book achieves what the author wanted to do in making something accessible to the general public, not just academics. It is neither pompous or boring. Instead, it's interesting and fun. In short... very highly recommended.