The 1900 and 1920 censuses are not indexed on Ancestry.com; the original pages in the handwriting of the census worker are what you look at, and you have to go through them yourself. I have found them really fascinating and not too difficult to search, either in a small town where you can go through page by page looking for your names, or in a big city when you know the address. In Soudan (St. Louis C.), I went through the whole town in a morning. For names in Minneapolis, I got a map through Mapquest and used it to find the census tract that I needed; then I went through the pages in that neighborhood. I'll admit it is somewhat tedious to go through the pages of addresses (usually 20-30 pages per census tract), but I think of it as following in the census worker's footsteps. If you follow the addresses on a map, you "see" him/her going up one side of the street, down the other, sometimes cutting across lots, or backtracking to get a house where--probably--no one was home the first time. In one case I found a family that eventually became an in-law living two streets over. The information on the censuses can be really interesting and helpful--dates of immigration and naturalization, length of marriage, occupations, people living in the household, ages, etc. (1900 and 1920 asked different questions.) In my family, I found out through the census that the man my great-aunt later married was living with the family in 1920 as a hired hand, which my mother didn't know. This fact helped explain some family attitudes toward that particular uncle.