Love skill cards, love this thing. I'll make this review simple and short.
Get an Unexpected Courage. This, in of itself is a brilliant mechanic, making Dream Diary unique among the research cards as being actually useful at 0xp. Also you get a skill, so it combos with Grisly Totem and can also be used on friends. It IS action intensive (takes 2 actions and 2 resources to start seeing a benefit, it starts getting good by the time youre using it for the third time) and takes up a hand slot but still. Very useful. Note that this cards's strength comes from flexibility, so if ALL you want to do is discover clues, look elsehwere, but if you want to make the occational , or test then Dream Diary is great.
All the upgrades then supercharge the mechanic by giving you a free Unexpected Courage to use every single turn that supercharges depending on which variant you go for, the options include being in combat, being at hard locations to investigate or playing the big-hand strategy. By the way, for those types that do nothing but investigating the upgraded variants are still totally worth it!
Brilliant card. Brilliant upgrades.