If you are looking for a quick nuts-and-bolts overview, turn to Schaum's Easy Outlines

Schaum's Easy Outline of Differential Equations is a pared-down, simplified, and tightly focused review of the topic. With an emphasis on clarity and brevity, it features a streamlined and updated format and the absolute essence of the subject, presented in a concise and readily understandable form. Graphic elements such as sidebars, reader-alert icons, and boxed highlights stress selected points from the text, illuminate keys to learning, and give you quick pointers to the essentials.

• Expert tips for mastering differential equations
• Last-minute essentials to pass the course
• Easy-to-follow review of differential equations
• Supports all the major textbooks for differential equations courses
• Appropriate for the following courses: Calculus I, II, and III; Mathematical Modeling; Introductory Differential Equations; Differential Equations