Hear Say evidence - layman's defination?

If you are testifying (in either example) with the intention of proving that Bill/Mary took the book, then it would be hearsay in both cases. In either case, if you were testifying about this but for a different purpose, then it would not be hearsay. For example, in situation 1: Let's say you are testifying about what Bob told you about Mary taking the book, and the testimony is intending to show that when Bob beat up Mary, Bob's state of mind was angry about Mary taking the book. Here the testimony isn't about whether or not Mary actually took the book, but rather Bob's state of mind. This isn't hearsay because it is not being offered to prove the truth of the out of court statement (Mary took the book), but Bob's state of mind.

Hearsay is "a statement offered in court to prove the truth of a statement made out of court," and is inadmissible (unless one of the exceptions applies). If the testimony is offered for a reason other than the truth of the out of court statement, it is not hearsay. However, it still must be relevant and competent, and not barred for being prejudicial.

In the second situation, it would be hearsay, but (assuming the trial is about Bill stealing the book) the statement is an admission by a party, and therefore a hearsay exception and allowed, because Bill (the assumed defendant) would have an opportunity in court to challenge that the statement was made, or he could argue he was joking, or he could argue you are lying, etc.

Hope this helps. Hearsay takes up about 2/3 of the evidence course at law school, so it is hard to explain in a few sentences.

Example 1 is hearsay and not admissible in court since Mary did not tell you directly. Bob could have made it up. Mary would not have the opportunity to "face her accuser" and challenge Bob's story, unless Bob were brought on the stand to testify himself.