Most Underrated Book:
I think calling The Beetle underrated is a little off, a better word would be neglected. I have these pulp phases where I read purely to feel the satisfaction of being fed a ludicrous story, so imagine my wide, wide smile of happiness after I finished reading this for our secondyear course on Popular and Genre Fiction in the 19th Century. I'm prone to thinking that most pulp authors are underrated purely because they're pulp (and because I am unwaveringly supportive of flagrant drama) so this shouldn't come as a surprise, more so because all of this book is sheer stupendousness. I realise this tag's become a reiteration of things I've already written about when it comes to books I like, which is why I should've saved myself from agonising over this and done the one on movies instead.
Most overrated book:
Agh, I don't know. I'm more often disappointed with the inability of a writer to sustain one brilliant book after another (what, and you're not?) than the reading of something unsatisfactory, so while the standard answers - Love Story, A Passage to India, and English, August - all stand, may I please take a minute to point out the sheer ghastliness of everything Zadie Smith has written after White Teeth? I couldn't get through either The Autograph Man or On Beauty so I doubt this applies as an answer. Doesn't mean my heart remains unbroken when this happens, though, I love the way she writes.