What is the difference between Insider's Essiental 500 Words and Insider's Essiental Guide to CR?

Test Preparation
1

<p>I am planning to buy some SAT prep books. I don’t know the difference between these two books.
<a href=“http://www.amazon.com/Insiders-Essential-Critical-Reading-Vocabulary/dp/0985291222/ref=sr_1_3?s=books&ie=UTF8&qid=1405223193&sr=1-3&keywords=sat+critical+reading”>http://www.amazon.com/Insiders-Essential-Critical-Reading-Vocabulary/dp/0985291222/ref=sr_1_3?s=books&ie=UTF8&qid=1405223193&sr=1-3&keywords=sat+critical+reading&lt;/a&gt;
<a href=“http://www.amazon.com/The-Insiders-Complete-Guide-Vocabulary/dp/0985291214/ref=pd_sim_b_1?ie=UTF8&refRID=1MTWGRS32K9JVXM4H70P”>http://www.amazon.com/The-Insiders-Complete-Guide-Vocabulary/dp/0985291214/ref=pd_sim_b_1?ie=UTF8&refRID=1MTWGRS32K9JVXM4H70P&lt;/a&gt;&lt;/p&gt;