Billy Pilgrim came unstuck in time

I was reading Slaughterhouse five by Kurt Vonnegut, which is an anti-war novel. It talks about the Dresden bombing of World War II (which, surprisingly, very few of us know about, inspite of its magnitude). But to make the book more interesting, the author tried something pretty strange ('good' strange).
The protagonist often finds himself in his own past and future. He can see and act in 4-dimensions (space-time).
The book starts like this:
Listen.
Billy Pilgrim came unstuck in time.
And ends like this:
Poo-tee-weet?

I do get random thoughts about the possibility of bustling through time, making ridiculous visits to see urself on a different day. But i always parried such ideas, simply because of the huuuuge amount of complexity associated with them. When every thought of yours results in a paradox, u would do well to stop thinking and thats what i do with time travel.
And all this usually happens when reading sci-fi thrillers. I always felt that sci-fi books on time travel were like buffalo sheds. You'll find that there is very little hard ground and a whole lot of crap (i have a copyright on this metaphor).

Is time an arrow? a line? a circle (as the hindus believe)? Is time irriversible?
General Relativity allows warping or bending of space-time and thus theoritically permits time travel. And if certain entities called worm-holes exist, a lot of particles are already, probably, making trips across centuries. But does it make sense that the past, present and the future are all happening together, right now? Thats the whole point. In a world where time travel is possible, there is no right now. Accept that first and everything becomes so convenient:)

Easier said. Ultimately, while dealing with the highest level of physics, it is usually advisable to work with mathematics and talk in equations. Paraphrasing Richard Feynman: whether you and I like it or not, the deepest secrets of the world seem to be written in a highly complex language. It is nothing short of blasphemy to try and talk physics in everyday terms.

And on a finishing note, the book is fantastic. It doesnt concern itself with time travel at all. That part is just incidental. It is primarily about war. And it features in the list of the top 50 works of fiction, of all time:)