I've been on this site for years. How am I just now finding the browser plug-ins? I am currently using a Chromebook ( an older model.) is there any plans to bring the plug-ins to browse books on other sites to Chrome? I use goodreads a lot, and brosing my 1000+ books on there if any are available would be easier than going back and forth to PBS. 
Thank you all for the help. Happy Reading.

browser plug in ????

It's under member tools at the very bottom of the page. Browser search plug-ins. It will add a search bar to your browser so you can search pbs without having to go back and forth if on another page and see a book you like.

In Goodreads, you can change your account settings so that there is a direct link to PBS on any book page you open in the Links button, under the summary, where it says GET A COPY. It searches by ISBN if there is one, otherwise it uses the title.