Well, After reading the Novel ‘The Invisible Man', I think the theme of the Novel would be Science-fiction and its summary would be-

‘The Invisible Man' is the story of an eccentric scientist named Mr. Griffin who after discovering the formula of invisibility tried it on himself and became invisible. The Novel explores the extent to which Human nature can go. He became invisible to create his reign of terror. The scientist arrives in a small village in South England. He is welcomed in an inn but after sometime the landlady became suspicious of his strange appearance because he was covered from head to foot in bandages and odd behavior as he always covered his mouth with something while talking. After a series of incidents, the village people started gossiping about him and his story started to go around. He managed to get away from them but after a fellow scientist betrayed him, the police started chasing him and he had to ho to extreme measures to protect himself. He wanted to kill Dr. Kemp for betraying him and more importantly he wanted to reverse his invisibility to become visible as only after sometime, he began to see the problems of being invisible. His end was tragic and we feel after reading this Novel what it feels to be invisible and isolated.

Hope this answers your question.