Greenwood was stabbed in the chest and neck in April. His body was discovered by his cleaner in the hallway of his Oxford home after the “savage attack”.
Michael Danaher, 50, of Hadrians Court, Peterborough, is on trial at Oxford Crown Court. He denies murdering the well-known member of the book trade but claims he killed him in self-defence.
According to a BBC report, in his opening speech to jurors at Oxford Crown Court, prosecutor Oliver Saxby QC said Danaher was interested in Greenwood's first edition of The Wind in the Willows.
Saxby told the court that Danaher’s intention was "to get money" by going to the houses of wealthy people and robbing them.
A spreadsheet was found on the defendant's computer with the names of 14 "people of means" who he intended to steal from or kidnap.
The weapon listed in many cases was "stun gun", and one was found in Mr Danaher's flat by police.
Saxby said Greenwood's name was on the list next to a note that read: "Modus: Any!! Expected take: Rare books."
Other people on the list are reported to be model Kate Moss and politician Jeffrey Archer.
Greenwood advertised for sale a number of items which included signed wartime photographs of Winston Churchill, a first illustrated edition of Frankenstein, an oil painting by George Bernard Shaw, and a 16th Century Bible.
He had been a dealer for the last 20 years, specialising in rare books but had wide ranging interests that included taxidermy and works by Banksy.
Although after 2011 he increasingly focused on writing historical books and biographies, he continued to attend auctions and fairs.
According to his website, Greenwood had started out in the trade by buying British Rail lost property and selling the items at car boot sales around London. He then moved on to antique furniture before starting to sell books online in 2000.