>>2025731The best book is the one about your specific area/region. Books and pdfs can be nice to look at but are absolutely pointless if they aren't about local fungi. Like the other anon said, learn one mushroom at a time- that also means familiarizing yourself with its lookalikes.
Don't be afraid to pick unknown specimens to bring them back for identification, the mushroom is only the fruiting body so you're not hurting the mycelium and you'll probably need to do spore prints anyway to make a positive id even of you think you know what you're dealing with in the field. Put them in a basket so they can spread their spores while you walk around. Don't eat more than a few during a serving, and no more than one kind at a time - you never know if you may be allergic to an otherwise nontoxic mushroom and if you are, it's better to have a fresh specimen with you to show the doctors. Some species are toxic on the first go, some gradually fuck up your liver until you realize you meed a new one. Don't be cocky, stick to what you know. Make sire you mark your trail if you wander off the path. Have fun, mushroom picking is a great to spend tome outdoors