Season 4 - 1999-2000

The episodes:

4.03 The Harsh Light of Day

4.06 Wild at Heart

4.07 The Initiative

4.08 Pangs

4.09 Something Blue

4.10 Hush

4.11 Doomed

4.12 A New Man

4.13 The I in Team

4.14 Goodbye Iowa

4.15 This Year's Girl

4.16 Who Are You?

4.17 Superstar

4.18 Where The Wild Things Are

4.19 New Moon Rising

4.20 The Yoko Factor

4.21 Primeval

4.22 Restless

In 1999-2000, Spike also appeared in "In the Dark", Angel: the Series episode 1.03