JANIS: Her Life and Music, by Holly George-Warren. (Simon & Schuster, 400 pp., $18.) “We get the full Janis,” our reviewer, Sheila Weller, wrote of this “masterfully researched” biography of the pop icon. But while George-Warren had access to Joplin’s diaries and letters (the latter of which are peppered with the word “SIGH”), she “zeros in” on her skill in singing, particularly the blues.