With even the most efficient chemical fuel we have to reach Alpha Centauri(closest star system to our own) in a human lifetime, you would need a fuel tank millions of lightyears across. So we need to get a lot faster should we want to escape out tiny little 200 AU(stopping at the termination shock)bubble that is our solar system. There are many ideas, but all of them contain a lot of sci-fi. Fission rockets, while not bad (principally) taking us around our SS, are too slow to get us lightyears away, also considering that they are quite inefficient(by universal standards, not by human standards). Fusion is at least several years away, and a lot longer before we can effectively use it as a propulsion method. And don't even get me started on antimatter and warp drives. Antimatter propulsion/Pion rockets, while proven to work, is a pipedream at best. We can barely make a few antiprotons in particle accelerators, and we would need kilograms of it, not to mention keeping it controlled until we want it to annihilate with matter. Warp drives are barely out of the realm of hypothesis, and we don't even know if they have any potential in principle, let alone in practice.
So far, what is the most practical design for a near light speed propulsion system, that could maybe put interstellar travel on the table for the first time?