Which season 5 episode is named after Barney's book of dating schemes?

The season 5 episode named after Barney’s book of dating schemes is “The Playbook.”

“The Playbook” is the eighth episode of season 5 and the 96th episode overall. It originally aired on November 16, 2009, with Pamela Fryman directing and Carter Bays and Craig Thomas writing. In the story, Barney returns to dating after his breakup with Robin and relies on his secret playbook.

The book contains elaborate cons designed to manipulate women into sleeping with him. Among its schemes is “The Lorenzo von Matterhorn,” which uses fake websites, a fake identity, and staged online information to make Barney appear famous and desirable. Another plan, “He’s Not Coming,” targets women at the Empire State Building.

Lily eventually steals the book and threatens to expose it online. Barney appears to abandon his schemes, but his apparent final play, “The Scuba Diver,” reveals that he has engineered an even more elaborate deception. The episode inspired a real book, The Playbook: Suit Up. Score Chicks. Be Awesome., published in 2010.