Introductory books are difficult to pull off. On the one hand, you want to present the subject matter in a way that novices can comprehend. But on the other hand, you don't want to dumb-down what you're writing about. As anyone knows who's ever tried to write an introductory text, this isn't an easy course to navigate.
Jim Herrick ambitiously offer an introductory exploration of a huge subject in his Humanism: An Introduction. Although Herrick is a good stylist and clear author, the result is mixed. He's at his best when discussing the history of humanism (chapter 2), humanistic responses to religion, morality and politics (chapters 3-6), and humanism and the environment (chapter 9). But he seems out of his depth in his exploration of humanism and science (chapter 7), his discussion of humanism and the arts seems platitudinous (chapter 8), and his rundown of institutionalized humanism (chapters 10 & 11) is boringly skip-worthy and way too long (taking up a full one-fifth of the book). Moreover, even the better chapters are short on argument and long on declaration. Finally, the book lacks a bibliography to guide further reading, an essential for any introductory volume.
So although Herrick's book isn't awful, there are better short introductions to humanism. Paul Kurtz's terse What Is Secular Humanism? (2007) may be the single best place to start. It's accessible but rigorous. Corliss Lamont's The Philosophy of Humanism (reprint, 1997) remains a classic, although dated in some sections. Margaret Knight's and Jim Herrick's Humanist Anthology From Confucious to Attenborough (1995) is a decent collection of primary sources. Finally, for those with a taste for Continental approaches, Sartre's Existentialism Is a Humanism (reprint, 2007) can't be beat.