Do you need to buy the reading books to effectively use the teacher and student books? OR can you use anybook on the subject? ALso where did you order it from? I thought that I might use this in conjunction with Usborne and TWTM.

I did level one a few years ago with my kids. I had a kingfisher first animal encyclopedia I used instead of the usborne natural world. So, I would say yes you could substitute. Basically in the first level you introduce the subject with your spine book, then the rest of the lessons/activities support your introduction. If you have read the WTM book, it is layed out as suggested in the book. The only difference is that the leg work is done for you. There is a book list, activities etc.

Edited to say that I got mine used on this board :) Thanks Lisa.

We do use the WTM but I hadn't seen it listed in the revised edition. But I hear everyone talking about using them.