Very similar to Part 1 & 2, this book is almost verbatim the lectures from the Coursera course "Greedy Algorithms, Minimum Spanning Trees, and Dynamic Programming" of the Algorithms Specialization, sections XVII-XXVIII. I don't just mean the lecture notes, but what the Professor/Author speaks in the videos. That's not necessarily a bad thing, but just something to keep in mind.
On its own I'd say the book is a good textbook, but its real purpose is to be supplementary material to the Coursera lectures. In Summary: If you want to learn Algorithms on your own, this isn't for you. If you are taking the Coursera Algorithms Specialization and find it easier to read than listen, this is a good book to get.
Also once Roughgarden published his book he removed the suggested readings from the other Algo text books, which... I find a bit annoying as I like to read multiple explanations of the same algorithm to get a better handle on it. Here are the other textbooks readings:
CLRS - Cormen, Leiserson, Rivest, and Stein, Introduction to Algorithms (3rd edition)
DPV - Dasgupta, Papadimitriou, and Vazirani, Algorithms
KT - Kleinberg and Tardos, Algorithm Design
SW - Sedgewick and Wayne, Algorithms (4th edition)
Week 1 (Two motivating applications; selected review; introduction to greedy algorithms; a scheduling application; Prim's MST algorithm)
CLRS: Chapter 16 (Sections 1 and 2) and Chapter 23
DPV: Sections 5.1.1, 5.1.2, and 5.1.5
KT: Sections 4.1, 4.2, 4.3, and 4.5
SW: Section 4.3
Week 2 (Kruskal's MST algorithm and applications to clustering; advanced union-find)
CLRS: Chapter 21 and Chapter 23 (Section 2)
DPV: Sections 5.1.3 and 5.1.4
KT: Sections 4.5-4.7
SW: Sections 1.5 and 4.3
Week 3 (Huffman codes; introduction to dynamic programming)
CLRS: Chapter 16 (Section 3) and Chapter 15 (Section 3)
DPV: Sections 5.2 and 6.7
KT: Sections 4.8, 6.1, 6.2
SW: Section 5.5
Week 4 (Advanced dynamic programming: the knapsack problem, sequence alignment, and optimal binary search trees.)
CLRS: Chapter 15
DPV: Chapter 6
KT: Sections 6.3-6.6
And for when Book 4 is published...
Week 1 (Bellman-Ford, All-Pairs Shortest Path)
DPV: 4.6, 6.6
KT: 6.8
CLRS: 24.1, 25
Week 2: (NP-Complete Problems, Beating Brute-Force Search)
CLRS Chapter 34
DPV Section 8.1, 8.2, 9.1
KT Sections 8.1-8.4, 8.10, 10.1, 10.2
Week 3: (Approximation Algorithms)
CLRS Sections 35.1-35.3
DPV Section 9.2
KT Sections 11.1-11.3, 11.8
Week 4: (Local Search, Wider World of Algorithms)
DPV Section 9.3
KT Sections 12.1, 12.4, 12.5