Between commas

I am reading side by side Criminal Procedure Updated Edition (2011) by Willard B. Riano and Remedial Law Compendium Vol. II, 11th Edition by Florenz D. Regalado. Fine books and complementary to each other, I think.

I'll have some upcoming posts on the books this weekend.

In the meantime that I am on leave from work I'll deal with minor typos. Here's something on page 2 of Riano's: 

My grammar teacher told me that a therefore in the middle of the sentence should be corralled by two commas. There's a trend, however, towards less punctuation.