Kovacsland is chock full of well-researched facts, and provides a good, fairly objective look at Kovacs' life and work. This provides a good balance to the other two books. The Phile is important because it was the first book on Kovacs, and Walley brings a unique flavor often writing in the style of Ernie's unique vernacular.  Sing is written by Edie. Reading all three provides a good all-around picture of the man. All 3 books are out of print.  Try Amazon or, better yet, eBay to pick up a copy.

In 1986, the Museum of Broadcasting, (later the Museum of TV & Radio and currently known as the Paley Center for Media) published a companion book in conjunction with its huge Kovacs exhibition called The Vision of Ernie Kovacs.  The book contains a TV videography, a lot of great stills as well as some well-written, loving critical essays of Ernie's work.

And, of course there is the novel Ernie wrote, Zoomar. There's also the book Ernie wrote (quickly) called How to Talk at Gin. Some libraries may have either of these on their shelves (if some fan hasn't permanently borrowed it). If you're library doesn't have them, you can borrow them via inter-library loan.  And of course, eBay is the best place to find copies of these (although a search for "Zoomar" will turn up a lot of vintage lenses, too) as well as of the many issues of MAD Magazine Ernie contributed to during the 1950s.