I'm a maths major and I have an interest in learning biology. I know very, very little; I know how babies are made and that's about it. Could anyone recommend a stimulating text to read for it's own sake and also to use to learn biology?
I found the Campbell Biology textbook to be quite comprehensive and approachable. I think many introductory biology courses use it.
There are tons of books and it is quite hard that gives such a broad overview. Here is a book that basically covered the first year of my Bachelor degree in biology. I am not sure it would be very stimulating though! If there is a specific branch of biology that interests you, let us know we'll be able to give you a better advice.
As a math Major you might enjoy some fields of biology that are highly mathematized. For example, system biology or theoretical evolutionary biology. For the latter, you might like to read this book from Martin Nowak. But I am afraid it might not be a nice idea to directly jump into some specific subject before having a good overview of the life sciences.
Otherwise you might appreciate some books of popular (but good level) science such as the Extended Phenotype from Richard Dawkins. This book is very stimulating and I think it starts with some basic definitions of biological concepts such those of "alleles" or "phenotype".
I gave you two examples of books from the field of theoretical evolutionary biology. Of course, one might give you tons of other examples of books of biology that might be at your level and fit your question.
Hope this helps a bit!