I want a book that gives a detailed account of building a rich front end interface like gmail.
is there one around?
There are books that go over concepts, but I need something to put it all together.
Guess I am looking for more of a 'solutions' approach, rather than a reference type book.
It depends on where you want to start, really. If you want to be able to hand-code the HTML, CSS and JavaScript on the front-end, you'll need to know and study myriad concepts, quirks, tips, bugs, standards and techniques. In that case, you'll need more than books, you'll need to start hacking. Good books I've read to help you here include Ajax Design Patterns[1][2] and JavaScript and Ajax for the Web [3]
If you want to have a toolset at your disposal that gets you most or all the way there without understanding the underlying web substrate, I'd recommend investing in a GUI building framework. GWT[4][5] or Flash/Flex[6] might be good ways to go.
GMail and other state of the art web applications are incredibly detailed pieces of work. Quite frankly, no book (or books) will tell you everything you need to know to build them. Hope this helps!