Genres -- Time Travel

I've read many books that are time travels but I've never written one. I've had several that are billed that way but they're really reincarnation novels. One even tied for a Time Travel award from Affaire de Couer a number of years ago. What's the difference between what I write and a true time travel. In my stories the main characters in the past lives are reincarnated in the present or perhaps even in a series of lifetimes. History plays a large part in these stories. History plays a major role in time travel tales. So what's the difference? Maybe only a mindset or editors not sure what to call these things I write.

Time Travel means a person from contemporary times is sent by some means to the past or someone from the past is brought to the present. I've also written fantasies where a person from our world is sent to an alternate world. One is strictly a fantasy world and the other is an alternate to ancient Egypt. These are not time travel either.

What I like about Time Travel books is the history and watching how the hero or heroine learns to fit into the new world. Sometimes I have trouble believing the method the writer chooses to send them to the past. I also have trouble believing that once a person has gone back in time that they can return to the present without bringing some nasty diseases with them. What if they ended in a time where smallpox or the bubonic plague was a threat? That gives me the chills,

So what do you think of time travel and what clever ways have you read that allow you to buy the theory of going back or forward in time.