Greetings Robert,
Welcome to the forum :)
It certainly is a very interesting field that you wish to specialise in, and I hope that you will succeed in it. Are there any particular aspects of Islamic history that interest you, and is there any criteria for the material that you read? There are much distortions of history and works written with much bias, so it may prove to be a challenging task. Often those who do not understand Islam or have no knowledge of it at all tend to allow inaccurate and weak information to blend into their work.
I am sure that many people can recommend good books for you to read - try searching and asking in the
Education forum for this.
You may also be interested to look through our
Biographies section, where you will find information about the life of the Prophet Muhammad (peace be upon him) as well as those who came after him.
May you have a beneficial and enjoyable stay!
Peace.