One really good online resource is the Museum of Hawaiian Shirts: http://themohs.org/
From their Golden Age history page:
Lasting a mere two decades and beginning more than a half century ago, the “golden age” of Hawaiian shirts has left an enduring fashion legacy. Once you have worn a World War II-era vintage “silky” rayon “Hawaiian” or “aloha “shirt,” you begin to understand what attracts so many zealous collectors who are sometimes willing to pay what seems like incredulous sums of money for what many people refer to as “just a shirt.” It is these very qualities, however, that has helped the Hawaiian shirt mystique retain its popularity. [...] In addition to the immense enjoyment that one receives from owning and wearing these shirts is the knowledge that they have proven to be a worthwhile investment, not only financially but to help preserve what has become part of our American heritage.
One of the better books I've found on the subject is a beautiful coffee-table book called My Freedamn! Seven -- Vintage Beach Fashions by Rin Tanaka.
Here are a couple shots from the book to get you in the mood:
Edited by bl@ster - 4/30/14 at 4:20am