The diary of Sir Roderick DeFoe is a book found in the Sir Roderick's bedroom in DeFoe Manor in 5 Days A Stranger. It contains entries written by Sir Roderick between 1805 and 1821. The text of the book is reproduced below.

March 5th, 1805
Work on the house is going well. It should be completed by the end of July. Belinda is already excited about the forthcoming wedding, and spends many hours of the day going over even the smallest details over and over again. Not since our early courtship has she been so giddy with joy. It softens my heart to see her smile, and she smiles often. I am wondering why I didn't retire sooner.
August 12th, 1805
I am only now having the opportunity to write this, as it has been a most hectic day. The wedding went without a hitch, and the house was ready for us to move in as soon as the ceremony was over. Belinda insisted on consummating our marriage immediately. I am sure, dear diary, this house can expect to hear the laughter of children before 1806 is out.
February 14th, 1806
A romantic day for our announcement; the physician has just left, confirming that Belinda is with child, a child we can expect to be born in June. We have already decided to name the child Matthew if a boy, or Jane if a girl.
June 28th, 1806
Belinda is dead. I will never forget her face, ash grey, contorted with pain. The child is healthy. Would that it had never come about and spared me this fresh hell.
May 24th, 1820
Matthew showed me the painting of the grounds he had created. I worry about the boy. Why can't he have healthier interests, like soldiering? The painting was fair, I suppose, but I would rather my child be less of a weakling.
June 28th, 1821
It is the anniversary of the night I unleashed a horror. A horror which I tonight shall remove from this world. May God forgive me.