you have to send your card code to your friend's e-mail by going to MyCards > Agent Card > Share. Type in your friends e-mail address and tell him or her to do the same. Here is one code P2FHHNDHXP. Add this card code to the Add Cards option and enter this code. you can do this with your friend's too.
Sorry there is no code that gives you every clue in the 39 clues add me to your allies:P2749NM7XP
add book codes
You Need To Have ALL 39 Clues collected to continue ADD ME! MY AGENT CODE IS P2RMHMMPXP Add Me My Agent Code Is P66P94C4XP
P2fhhndhxp COMPLETE MISSIONS. ADD CARDS. UNLOCK CLUES.
There is none but you can add this card P3WKMFH2XP
add this card:p2mw6wtpxp
Silver add me to your allies:P2749NM7XP
It is possible to get all of the 39 clues in a day, but you would have to add a whole lot of cards, but currently as of June 1st, only 37 clues are available.
click on their card and press add
log onto the 39 clues web site and type in this code in the add a card place and the code is:p4pwnxmwxp
Wormwood add me to your allies: P2749NM7XP
pj78dw3n78 add me!! DolphinAqua261