Biographies in Context is a great library database for getting brief but informative biographical summaries of noted people.
The other good one is American National Biography. It only does Americans though.
Finally, all the British people are in the Oxford Dictionary of National Biography.
Sure, you could use Wikipedia for this, but sometimes non-experts DO get small details and historical events wrong. Plus, you don't have to wade through the controversies that polemical figures (such as economists) engender on the W.
I would rather get you all the facts so you can decide what it means. Especially after you read the original source material after getting this grounding.