Justin "Jdog" Marks, born in England, is a pickup instructor and founder of the Arizona Pickup Lair, though he is probably best known for being Mystery's co-host on season 1 of VH1's reality TV show, The Pickup Artist.

He graduated from university in 1995 with a degree in engineering and worked in telecom. Soon after, he started his own multi-million engineering company. Despite his business success, he still had little to no success with women.

Frustrated but persistent, Jdog went on a journey in 2000 into the seduction community. He has since gone on to found the Arizona Pickup Lair and his own pickup company, and has been featured on season 1 on VH1's reality TV show, The Pickup Artist. Jdog is known as a leading day game expert and also owns his own in night club venues.

Having been exposed to the seduction community, Jdog traveled to meet and learn from the world's most revered Pickup Artists, such as Mystery, Neil Strauss, Lance Mason, Tyler Durden, and many others. In the process, he became a master and teacher of the art himself, respected and known internationally.