This book describes comprehensively a method for playing D&D 5e published adventures solo. There are some books that adress the solo rpg topic already (I would like to mention specially Kevin Crawford's Scarlet Heoes for OSR) but I would say there was a gap related to solo playing of 5e published material.
The method described is solid, consistent and well structured. Obviously, as D&D is conceived for multiple players and a DM, the material by itself presents some inner dificulties to be adapted for solo playing. However, Scutt has been working on ways to adress these difficulties quite successfully, assuming some of them can't be completely overcome.
One of the pilars of the method is the choice to use just one PC and a sidekick one level higher than the adventure requires, and applying some easy special rules to tackle with the adventure's challenge. Scutt emphasizes the immersion as a key aspect to get fun from a D&D experience, and this is the reason because there are many pages describing an immersion system, which in fact is very quick to apply while playing. Scutt's also gives precise notes on how to read the D&D adventures, revealing that the WotC books are designed in a way quite suitable for solo gaming. An easy but effective AI system to rule the monsters is given as well.
This method allows to play adventures by your own, for enjoying them as a player before to GM them, or just by the pleasure to play D&D without depending on others' agenda. As the work is solid, all the key elements are adressed, and the method is consistent, I consider this book is a must if you want to play solo D&D adventures, or play with one PC and a GM. It's important to note that the aspects of the method are accurately described, reducing chances to leave questions unanswered.
I would like to congrat Tom Scutt for DM Yourself, an recomend you the book. I am eager to purchase the second book soon.