When Is A Textbook Not A Textbook? September 26, 2010 by Larry Ferlazzo | 0 comments Jason Renshaw, ESL/EFL blogger and author of the popular Boost! English language learning textbook series, has a nice post and video about how ELL students and teachers can create their own textbook instead of using a published one. Check-out Watch an ELT author “unplug” his own coursebook! Share| Author: Larry Ferlazzo I'm a high school teacher in Sacramento, CA.