Wide Field Camera 3 (WFC3) will have a broad range of inquiry, from early and distant galaxies beyond Hubble's current reach, to more nearby galaxies with "stories to tell" about their star formation histories, to the planets in our solar system. Along the way, "dark energy" will be seriously probed by WFC3. The instrument's key feature is its ability to span the electromagnetic spectrum from the near ultraviolet through the optical (to which our eyes are sensitive), and into the near infrared. WFC3 is the only Hubble instrument with this "panchromatic" capability. WFC3's strengths complement those of the Advanced Camera for Surveys (ACS) should it be repaired. Working together these two instruments could create the greatest era in the spectacular history of Hubble imaging. The Servicing Mission 4 astronauts will remove the Wide Field Planetary Camera 2 (WFPC2) installed during Servicing Mission 1 in 1993 and install the WFC3 in its place.