Most helpful book on wood ID that I`ve found is `Identifying Wood` by R Bruce Hoadley , The Taunton Press . The article referenced in the link below is worth reading . If you want lots of pictures , check out Hobbit House .
If you want tree ID for Illinois , try Trees in Canada ( also published in the US as , I think , Trees of the Northern US ) by John Laird Farrar .
The USDA plants database website is an excellent resource for info on all N American native trees , although identifying wood from it would be hard .
The Wood Explorer data base and The International Wood Collectors Society may also help .
The Truth Behind Wood Identification | The Wood Database