It's a very short book with only 4 chapters, but every chapter is padded with a summary and the book ends with a summary, so mostly repeat content.
The book's title says read a book a day but the first chapter begins by stating it's "biologically impossible" to read fast and goes into a long discussion about the reason.
The next chapter doesn't discuss reading but everything you should do to prepare for reading. This chapter makes up 40% of the book, but has nothing to do with actually reading, only systems like SQR3 or 4P's on how to start reading.
The next chapter finally gets to the "meat and bones" as Peter calls it to actually increase the speed of reading, but is only three outdated tips sub-vocalization, word-chunking, and skimming. He himself admits subvocalization doesn't always work and he he barely gives any instruction on word-chunking, only a link to another resource.
The last chapter is suppose to offer tips on improving comprehension but mainly covers eye fitness and not comprehension. Then he spends four paragraphs recommending someone else's book David Butler's Speed Reading with the Right Brain.
There are some tips on retention but there are very simple like take notes, summarize, and use mind maps.
Very little of this short book with a lot of summaries is on speed reading with the author not convinced that it is even possible, which explains why he doesn't give direct tips to increasing reading, only padded fillers.
I would not recommend it, skip this book and just go with David Bulter's Speed Reading with the Right Brain, which the author himself recommends.