Simplify the following text for a Grade 7 native English-speaking person.
Original: Howard Phillips Lovecraft ( August 20 , 1890 â `` March 15 , 1937 ) was an American author of fantasy , horror and science fiction .
Simplified: Howard Phillips `` H. P. '' Lovecraft ( August 20 , 1890 â `` March 15 , 1937 ) was an American author of horror , fantasy and science fiction , especially the subgenre known as weird fiction .