The Good Books depends upon which specific field you go into. The first step is to pick a field that you're interested in. This is often the hardest step, because from a 10,000-foot level, you often can't tell what will be interesting, and whichever field you dive into will shut off various other opportunity costs.
Then, go to your favorite graduate school website. I'm partial to Stanford and MIT, because both put up fairly complete syllabi on the web, including textbooks and often homework assignments. Pick out a couple courses, just as if you were back in college, and note down the textbooks.
Then go to Amazon.com (or Amazon.co.uk, when I was in college Europe had much better textbook prices, I dunno if they've closed that loophole) and search for those textbooks. And when it pops up "Related books" with good ratings, add those to your cart as well. Buy them.
Read, rinse, and repeat. Many textbooks have generous citation indexes that you can use to find further books or papers to check out.
Then, go to your favorite graduate school website. I'm partial to Stanford and MIT, because both put up fairly complete syllabi on the web, including textbooks and often homework assignments. Pick out a couple courses, just as if you were back in college, and note down the textbooks.
Then go to Amazon.com (or Amazon.co.uk, when I was in college Europe had much better textbook prices, I dunno if they've closed that loophole) and search for those textbooks. And when it pops up "Related books" with good ratings, add those to your cart as well. Buy them.
Read, rinse, and repeat. Many textbooks have generous citation indexes that you can use to find further books or papers to check out.