Simplify the following text for a Grade 9 native English-speaking person.
Original: This was a compilation of his letters to Thomas Pennant , the leading British zoologist of the day , and the Hon . Daines Barrington , an English barrister and another Fellow of the Royal Society .
Simplified: This was a collection of his letters to Thomas Pennant , the leading British zoologist of the day , and the Hon . Daines Barrington , an English barrister and Fellow of the Royal Society .