brain teaser

[Brad100]

12. A rich man named Stuart Laidlaw had been counting his money.
When he finished, he accidentally left a $1000.00 bill on his
desk but when he returned for it a short while later, it was
gone. Only two other persons could have seen the bill. One was
the cook; the other was the gardener. The cook told him that she
had hidden it for safekeeping under a green book that was on the
desk. But when they looked the bill was not there. The gardener
said he had found the bill where the cook had left it. He had
placed it inside the book, where he thought there was less
chance that somebody would find it. He had written down the page
numbers so that he would not forget them. The bill was between
pages 45 and 46, he said. But when they looked, there was no
money in the book. After Mr. Laidlaw had talked to the cook and
the gardener, he called the police. He was sure he knew who had
taken the money. Who was it, and how did he know?

[Muffet]

The gardener. In normal books, 45 and 46 would be the two sides of one page, so no space in between.