sentences:  Many titles on advanced topics are also available, such as complex variables and topology, but these may be harder to find in retail stores.Schaum's Outlines are frequently seen alongside the Barron's "Easy Way" series and McGraw-Hill's own "Demystified" series.The "Demystified" series is introductory in nature, for middle and high school students, favoring more in-depth coverage of introductory material at the expense of fewer topics.