| Name | First Aired | Runtime | Image | |
|---|---|---|---|---|
| S04E01 | 401 |
November 6, 2013
PBS
|
27 | |
| S04E02 | 402 |
September 21, 2015
PBS
|
27 | |
| S04E03 | 403 |
September 16, 2008
PBS
|
27 | |
| S04E04 | 404 |
October 15, 2013
PBS
|
27 | |
| S04E05 | 405 |
September 30, 2008
PBS
|
27 | |
| S04E06 | 406 |
October 7, 2008
PBS
|
27 | |
| S04E07 | 407 |
October 14, 2008
PBS
|
27 | |
| S04E08 | 408 |
October 21, 2008
PBS
|
27 | |
| S04E09 | 409 |
October 28, 2008
PBS
|
27 | |
| S04E10 | 410 |
November 5, 2008
PBS
|
27 | |
| S04E11 | 411 |
November 12, 2008
PBS
|
27 | |
| S04E12 | 412 |
November 19, 2008
PBS
|
27 | |
| S04E13 | 413 |
November 26, 2008
PBS
|
27 | |
| S04E14 | 414 |
December 3, 2008
PBS
|
27 | |
| S04E15 | 415 |
December 10, 2008
PBS
|
27 | |
| S04E16 | 416 |
December 17, 2008
PBS
|
27 | |
| S04E17 | 417 |
December 24, 2008
PBS
|
27 | |
| S04E18 | 418 |
December 31, 2008
PBS
|
27 | |
| S04E19 | 419 |
January 7, 2009
PBS
|
27 | |
| S04E20 |
420
season finale
|
January 14, 2009
PBS
|
27 |
No artwork of this type.
No artwork of this type.
No artwork of this type.