The Great Trouble by Deborah Hopkinson

Eel is a homeless orphan in London, 1854 who works odd jobs to support himself and his little brother.  All the while he must avoid his evil stepfather who wants to turn him and his little brother into beggars and burglars. When cholera strikes in his neighborhood he is enlisted by the famous doctor, John Snow, in a desperate effort to find the cause of the epidemic.  This historical fiction is based on an actual outbreak of cholera that lead to the discovery of how the disease is transmitted.  This book was an OK historical fiction, but came across a little didactic. Dr. Snow spends a good deal of time teaching Eel--and through him, the reader--the method of scientific research. That said, Eel is a likeable character, as are several of the other characters in the book. A lengthy note at the end of the book explains which characters and events are fictional, and which are based on actual people involved in the historical event.  I couldn't help looking up John Snow on my family history to see if there was any relation, but no.(249 p)