(Link for full interview below)

…how much influence you have on scripts. Are there particular scenes or dialogue you can take credit for?
That's an excellent question. I have been very pleased. This is the most I've been allowed to play. I pitch jokes constantly. I don't come up with solid gold all the time, but if it's funny, we'll put it in. My system is, if it's in the middle of a scene, I'll pitch it to the writer beforehand. Every episode, we have the writer for that episode on set. If it's at the very end of a scene, I'll do the scene as written, give it two seconds so they have the opportunity to cut away when the scene is over, and then throw the joke in at the end. I don't mind surprising people at the very end…. When were playing laser tag, and I was embarassed that I didn't invite Kate Beckett [Stana Katic] in and I used the gun to shoot myself in the mouth, that wasn't written in the script. That was a little something I threw in there. When the prostitute called me back, I said, "Just out of curiosity, what are you wearing right now?" Those things you can throw in at the very end of the scene because they can opt to cut it out at any point.

Multiple Firefly fans would like to know if they're just looking for shoutouts in the dialogue, or if the references they're hearing are intentional.
Let's just say that any time I can give a shoutout with a Firefly reference, I will. I've also given shoutouts to One Life to Live. I've also stolen lots of jokes from Ryan Reynolds from Two Guys, a Girl, and a Pizza Place. I'm a plethora of stolen jokes and kitschy references.

So the "five by five" from last week's episode was in fact a reference to Faith from Buffy the Vampire Slayer?
Yes.

Another popular question: When and how are we going to deal more with Beckett's mother's death? [CRYPTIC SPOILER ALERT!] The press release for the season finale ends with "…while looking into Beckett's past, he unearths information that could end his relationship with her forever." Does that have to do with Beckett's mother?
[Silence] I wouldn't want to spoil the season finale.
Be a man, Nathan. Give us something.
I'm trying to think what I can say… [More silence] I'm gonna keep that a secret. It's really well orchestrated. I don't want to blow anything.

So you probably won't answer the follow-up question: Is there a story line in place to keep Castle and Beckett working together once his book is published?
Is there a story line in place to keep them together?…You know what, I'm gonna have to be totally surprised along with the audience, because I have no idea what's happenin' next season.

Tell us what you're hearing about a Season 2. How are you feeling about the chances for renewal?
I told myself a while back, "Love what you do, but don't fall in love with what you do." That way you won't be brokenhearted if ever it gets canceled five episodes in — which has happened to me. Everything that's in my control, those are the things that I worry about. Once it's out of my hands, I try not to worry. I read the paper like everybody else. Everything looks pretty positive so far.

I love this question, asked by several readers: If you were to write an episode of Castle, what is the one thing you'd want to see happen in it?
I'm dying to see Richard Castle's ex-wife played by Monet Mazur again. I think she's a lovely lady, an incredible actress, and sorely underused.

• For full interview visit http://popwatch.ew.com/popwatc…..lio-1.html