Note: Fake, prop books used in the show are not included in this list.
Episode 1: "Work That Body for Me"
Piper: Funny Girl by Nick Hornby
Yoga Jones: High Fidelity by Nick Hornby
Episode 2: "Power Suit"
Black Cindy: What Makes Sammy Run? by Budd Schulberg
Red: My Beautiful Ballooning Heart by Janice Silverman Rebibo
The rest of the books in the pile seem to be prop books.
Episode 3: "(Don't) Say Anything"
Taystee: A Song of Ice and Fire series by George R. R. Martin
Poussey: Bad Kid by David Crabb
Poussey: The Longest Way Home by Andrew McCarthy
Episode 4: "Doctor Psycho"
Red: Essentials of Classic Italian Cooking by Marcella Hazan
Suzanne: Dhalgren by Samuel R. Delany
Episode 5: "We'll Always Have Baltimore"
Abdullah: Emotional Intelligence 2.0 by Travis Bradberry and Jean Greaves
Poussey and Soso: books by Rainer Maria Rilke
Aleida: Trigonometry Essentials Practice Workbook with Answers by Chris McMullen and McGraw-Hill Education Science Workbook for the GED Test
GED® Math Test Tutor by Ms. Sandra Rush M.A.
Poussey: Pêcheur d'Islande by Pierre Loti
Different edition but same book.