Not quite a book, this work was actually compiled from Rothko's papers after his untimely death. As a consequence, it delves into a plethora of different topics. Sometimes, it even makes abrupt jumps to entirely different tracks between chapters. One recurring theme that emerges is Rothko's vehement defense of his work as figurative rather than abstract. The word "abstract" seemed to be one that he held in particular disdain, especially when it was hurled at him by critics.
On a side note, Mark Rothko endured a lifelong battle with despair, which ultimately led him to take his own life. It is almost impossible not to read this profound sense of melancholy into his paintings. If you have ever had the privilege of seeing one of his works in person, you would be struck by their ponderous nature, their heavy-weighted presence, and on the whole, their quite somber tone.