Well you can't directly email people.

I hate spam.

If people had their email addresses available they would be harvested by spam bots.

To try and stop spam I have secured your email addresses behind a mechanism. It is like a private message system.

To suggest a swap, you must first enter your own swaps and needs, after saving your swaps you will see a list of potential swappers eg

   Potential swappers: (only visible to owner of book after first save)
   Click on a name below to start a swap check. Swappers appear if they have swaps available and
   have their email   field set.
   DEL TEBBIT-1 29   -   Mat Homes-1 15   -   Pip Kingsley-1 8 

When you click on the name, if you have a matching swap, then you have the option to contact them:
     blah blah...
     Send email to request a swap.

Click on that and an email will be sent to the swapper's address with a link to the swap details.

NB You do not get a copy of the email, as this would betray the email address.

NB The email contains your email address, so they can contact you if they like the swap.