Dr. Henry Pym, started out as a scientist who just wanted to make a difference, developing a formula that is capable of shrinking whatever it comes in contact with, as well as a formula designed to restore it.
After a bit of a miss-adventure he set’s aside this idea as a failed cause, until one day he and his assistants are held captive at the hand of communist spy’s. It is here that he puts on the Ant-Man costume for the first time, having found a way over time to communicate to the ant’s. He peruses a solo career as a crime fighter and superhero stopping both common thugs and communist plots for a period of time.
With time we learn about Maria Trovaya Pym, his now dead wife, and how he had failed to save her on a trip to her home country of Hungary. This is what led him more than anything else after his discovery to begin to prepare for the day when he would put on the Ant-Man costume and become a super-hero.
But it is also though this that we learn that he needs an assistant, someone to fight at his side, He selects the daughter of Dr. Vernon Van Dyne after his untimely demise at the hand of an alien creature From Kosmos. Seeing in her both the attributes he desires as a partner, and an appearance much like that of Maria Trovaya Pym. As such Janet Van Dyne becomes his partner, known as The Wasp.
Later Dr. Henry Pym as Ant-man and Janet Van Dyne become founding members of the Avengers.
Reading Order & Appearance list for Dr. Pym(Ant-Man / Giant-man):
*Based of of what I have reviewed so far: